It's certainly true that Prasannan Parthasarathi, the author of Why Europe Grew Rich and Asia Did Not: Global Economic Divergence, 1600–1850 (2011), which is the main source cited by the Wikipedia article you're linking to, argues that the wages of some more prosperous Mysorean workers – specifically, weavers – were ahead of those of their European peers at the time that Tipu Sultan's kingdom fell to the British. And, since Parthasarathi writes of the years around 1800 – only part-way through the period known as the "Great Divergence," which saw the west's economic performance pull ahead of that of the economies of Asia, and before the period in which that divergence really accelerated – this is certainly very possible.

However, looked at more closely, the statement that "Mysore had some of the world's highest real wages and living standards in the late 18th century, higher than Britain," made by the author(s) of the Wiki article "Economy of the Kingdom of Mysore", is the product of some basic errors and challengeable calculations. Essentially the Wikipedia article takes several different sets of data and runs them together in an attempt to make that case, but in doing so makes claims that none of the original authors actually do.

Let's break this down. The statement made by the Wikipedia article rests on the following series of claims:

1. Average per capita income in Mysore in c.1800 was five times above subsistence level

2. "Subsistence level" equates to a wage of $400 in 1990 international dollars

3. Thus average per capita income in Mysore was $2,000 in 1990 international dollars

4. British per capita income in 1820 was $1,706

5. Therefore, real wages and living standards in Mysore were higher than the equivalents in Britain

Turning to Parthasarathi, we find that claim [1] is based on calculations made by the Indian economist Sashi Sivramkrishna in his paper "Ascertaining Living Standards in Erstwhile Mysore, Southern India, from Francis Buchanan's Journey of 1800-01: An Empirical Contribution to the Great Divergence Debate", which in turn rest on series of data collected by Dr Francis Buchanan, who was commissioned by the East India Company to survey its newly acquired possessions in southern India after the fall of Mysore in 1799. This survey was highly detailed and in fact remains unparalleled in terms of the wealth of detail and reliability it offers. Nonetheless, it was not designed to be used by 21st century economists, and Sivramkrishna acknowledges the limitations of the Buchanan's datasets. He attempts to get around these by constructing a notional daily "subsistence basket" of essential goods, comprising

500 grammes of millet

100 grammes of lentils

10 grammes of ghee or oil

A portion of cloth equivalent to an annual total of 12m x 0.8m

A long series of calculations follow, but Sivramkrishna concludes that the Mysorean weavers surveyed by Buchanan would have had to spend only about a fifth to a quarter of their wages to purchase this daily subsistence basket. We can see how, based on this, Wikipedia makes its claims, and in fact Sivramkrishna also suggests that, on this basis, wages for Mysorean weavers were on a par with those of weavers in Europe. But note that the claim really only applies to weavers, not to an average of the wages or incomes of all the subjects of Tipu Sultan. I'll come back to this point in a moment.

The real problems begin with claim 2, which is sourced not to the work of Sivramkrishna and Parthasarathi but to Angus Maddison's The World Economy Volume 2: Historical Statistics (p.260). An examination of the relevant portion of this document reveals some significant problems: first, Maddison's $400 figure relates not to 1800, but to the period "from the first century to the end of the first millennium" (ie, from 1 to 999 AD); second, it is an extraordinarily broad estimate, covering not merely Britain, but an average of the whole of Western Europe plus "the Americas, Australasia, Africa south of the Sahara, Eastern Europe and the area of the former USSR"; and, third, it is itself the product not of any calculation, but merely of an assumption that the figure should be somewhat less than that Maddison separately calculates for China in the first millennium CE as a whole ($450 per capita), to take account of the economic collapse the author assumes happened across Europe after the fall of the Roman empire.

It's not really fair to take Maddison to task for this series of really very broad assumptions, since they were certainly not produced in an attempt to allow comparisons to be made between per capita wages in southern India and Britain in 1800. However, the fact that the Wiki author has failed to notice the figures they have used apply to a period a thousand years before the one they are attempting to draw comparisons with hardly inspires confidence in the remainder of their calculations.

Finally, it's worth returning to Sivramkrishna's calculations to make two more points. First, the author himself points out that it's possible to produce a second notional calculation of a "subsistence basket" in the Mysore of 1800, this one based on the staple food being rice rather than millet, and come to the conclusion that Mysore weavers were living at subsistence level, not with an income four or five times that level. Second, as I noted above, Sivramkrishna's calculations do not refer to average wages in Mysore at all, but rather to the earning power of artisans – weavers – who were actually close to the top of, if not actually top of, the working class earnings scale in Mysore in 1800. The average citizen of Tipu's Mysore would have earned significantly less than that, and in fact Sivramkrishna acknowledges that Buchanan's survey suggested that the local peasantry lived not far above basic subsistence level, which is pretty much what one would expect. It's therefore rather dangerous to assume that, even if the wages of Mysorean and British weavers were roughly comparable in this period, those of British farm labourers and Mysore subsistence farmers were equally on a par.

We can draw the following conclusions:

1. Average per capita income in Mysore in 1800 was not five times above subsistence level. That figure applies solely to Mysorean weavers, and then only on the basis of one of two alternate calculations of the cost of a "subsistence basket". The average Mysorean peasant appears to have lived at a little above subsistence level.

2. The idea that a subsistence wage was worth $400 in 1990 dollars is the product of a severe misreading of Maddison, and hence Wikipedia's calculation of an "average per capita income" for Mysore in 1800 is fatally flawed in any case.

3. Thus it's not possible to make any meaningful comparison between the average Mysorean "wage" of 1800 and the average British wage of 1820.

I'm sorry to go into such exhaustive detail, but I wanted to try to be fair to all parties. The tl;dr is that the author of the Wikipedia article has attempted to stitch together a variety of very disparate figures and calculations to make a comparison none of the academics concerned ever anticipated being made, and has made significant errors in attempting to do so.