For the taxi side mission, what you've got isn't strictly correct.
You complete the taxi side mission when you do either of these two things (whichever comes first):
Complete 50 taxi fares
Earn $5000 from taxi fares
If you got, I don't know, a 30 in a row or something, you'd have reached $5000 (just an estimate) and this would count. But if you kept failing after 4 in a row etc, you'd keep going for 50 fares and complete it that way. This has been confirmed, btw.
ALSO! This should be renamed to 100% Completion Guide - PSP Version
As it is different for the PS2.