having an educated guess at what legal porno and the like pay for their scenes (dp's tp's and all the other p's) i do not think you are far off the mark.
I just got in touch with Isabella's agent (Russian-based JulModels) to ask about her rate for a porn shoot whilst she's in London...
It's 500 euros if anal is involved. Plus 20% agency fee. So 600 euros. That's what "Legal Porno" or any other producer
, big or small will pay. Also that's not for an hour that's for the whole shoot
. Up to about 4 hours is normal for a porn shoot apparently - but girls don't fuck for 4 hours straight. But she might fuck for 2 hours. Which means that the porn shoot option is cheaper than booking her for a punt!
Only trouble is (and I've looked into this) you would need a number of things to convince that you're a producer and not a punter. For example: a certificate showing you're STI tested (yes even if the shoot will be done using condoms you still need to prove you're clean and I'm not sure she would accept a punting phone with a text containing test results from Dean Street Express!); professional camera; lighting; ideally a studio; camera operator and other crew. The model agency will not send girls to a 1 on 1 meeting basically.
So now it's clear to me why these girls are tempted to escort when away from home on a porn shoot. They get more money for the escorting and it's probably easier work for them too. Most of us aren't hung like your average male pornstar nor have we their stamina.
No I'm not starting a career in porn but I've always been very interested in it!