Q:

Manage abbreviations before parantheses at the end of a sentence

There are already topics very close to my question, but not quite there.
Does anyone know what to do about this:

We review our accounts p.a. (at the end of the year).

Normally, without the text in parentheses, the "." after "a" would suffice to end the sentence, but then the parentheses come into play.
Should there be another period after the parentheses like in my example, or no?

A:

Well, yes, otherwise any sentence that contains an abbreviation and parentheses would not end with a full stop. Consider this:

She yelled out "stop your B.S." (a common abbreviation for bull excrement) at the top of her lungs. 

It only confused you because the parentheses are at the very end of the sentence. If there is more text following them, it is clear that punctuation is needed. 
The periods of abbreviations only serve as full stops if that usage will avoid consecutive punctuation marks. If that is not the case, normal rules apply.

