I'm just guessing here(all of my activities are available for clients to see on p411) but maybe some girls are afraid to list all the things they do because the pay schedule may be different for something(what if she offers greek or some other service) for an additional price but since there's no way to indicate that other than her bio which many guys don't read she might just say forget about it. Some girls offer different levels of service depending on how nice the guy is and how well they click but are afraid to check the YMMV box because they fear it conjures up a girl that's going to try to upsell them on everything. YMMV has gotten a bad reputation but it seems like common sense to me- however I ONLY list things that ANY average client can reasonably expect to receive as services....the YMMV is because SOMETIMES I might deep french kiss but mostly I don't so I just don't check Deep French Kiss as a service.
Also, some girls are just shy(yes, even in this line of work) and would rather meet the guy before they put down on paper what activities can generally be expected of them with any client that passes screening. Some girls think putting all of those intimate details out on the internet is crass and they opt out of reviews as well for that reason.
WALDT. Feel free to check out my profile on P411 though- all the activities listed are what the average client can expect to be offered (at no additional charge) if he'd like them.