Methanol compared with acetonitrile

I read from STMS that methanol usually gives higher sensitivity with
ESI and APCI. Why is it so? I know that under RP, we would use higher
conc. methanol to get similar RT. That would give higher ionization
effeciency under ESI. But in APCI, everything is evaporated. There
should be no difference except for the needle caburization issue.

Is it always true that methanol gives higher sensitivity, regardless
positive or negative mode, ESI or APCI?

Thanks in advance for your kind reply!