It seems that the SOPs at the AMPs differ from region to region.
In some places, they are more spa-like. You go in, pay the HOUSE fee (usually less than or up to 100, depending on location). As you are being showered or massaged, other stuff MIGHT happen but you somehow have to get the conversation going because each masseuse will be different. If all you paid was the HOUSE fee, then you got what you paid for: a shower and a massage! Some girls will NEVER be the first to bring up services or money but wait for the customer to ask about extra services. Others might be a little more daring and drop hints or invites. The girls make extra by tips for extra services.
In other places (NYC), there are spa-like places but also plenty of AMPs with a well worked out routine: two calls to get there, enter, to the room, undress for shower, shower, back to room, FULL flat-rate fee up front (HOUSE plus masseuse fee), masseuse leaves the room for a few minutes and returns with supplies; she knows what to do from there on!
"High end" AMPs in NYC have yet another SOP.
I'm sure there are other variations on the AMP theme.
I suggest you ask on your closest regional board what the SOP is at the local AMPs. You should be VIP and read the DETAILED reviews of the local AMP experiences. If the reviewer isn't explicit ("I had to ask her to do more." or "I didn't have to say a thing and she knew what I wanted next."), you can always send a PM and hope for a friendly reply