Examples?

It's very simple - casualties exceed the official TO&E because casualties include replacements.

Say your company originally had 100 soldiers but 50 became casualties after the first month. They are replaced but then the company suffers another 60 casualties on the second month. Hence, the company had suffered 110 casualties - or 110% losses. But if you count the total number of soldiers who served in the company you'll find that they actually had 150 serving soldiers (100 originals, and 50 replacements) of whom 110 became casualties - or just over 70%.

In some cases the replacements include men who were wounded and returned to duty, so the same person may end up being counted as a casualty two or even three times.

Note that armies also counted casualties differently. The German Army in both the First and Second World War did not count lightly wounded men that would have been considered "casualties" on the Allied side. This is why comparing casualty figures by two combatants is usually a fruitless exercise.