I'd humbly offer a word of disagreement... I personally believe that it is entirely up to the companion which hour is more taxing on her heart, mind and body to graciously provide; the first, the second, the third, the fourteenth, etc.  
If, to her way of thinking, maintenance of her high standard of care for her beloved gentleman friend requires an extra one hundred dollars, a talking Polynesian pig, a Woodstock '69 ticket stub, a ride on SpaceX and a partridge in a pear tree, well, then it is her sacred duty to communicate that requirement to her potential gentlemen friends through her website, just like it is your prerogative to refrain from engaging her services if you find anything about her or her advertisement distasteful.  

What I cannot understand, however, is how an educated, respectful man could deign to employ outdated, pejorative words like "hooker," while further implying that it is a dearth of arithmetic skills which account for her request for her second hour's services, instead of what it really is: precisely what she needs to maintain her standard of care to her gentleman friend - no more, no less.  

To assume that the second hour with a gentleman friend is "never as physically demanding as the first," is to assume that companions are robots for whom a date is nothing more than an impersonal session at the gym on the equipment of her gentleman friend.  Not only that, but the foregoing assumption erroneously implies that the only resources a companion sacrifices are physical, thereby discounting any emotional and mental care expended in the production of an unforgettable date with her.  Furthermore, the assumption that you have personal, expert insight into how much effort or energy this particular companion expends during her second hour, and in your expert opinion it is "without much additional effort," is to know that you view companions as interchangeable robots, with identical needs in each of the hours of the date, and with identical, robotic and interchangeable energy requirements.  

Please forgive me if I sound too impassioned, in your defense I believe that some men may not fully understand everything it takes some women to pull off an unforgettable date, time and time again (simply because most women are so good at covering its true cost!)  Which leads to those men thinking that it's easy, or at least to not understanding what it's really costing her.  I truly don't mean for you to take this as an attack on you personally, but rather as an exposition and hopefully just something to think about.  

Much love and XOXOXO, Grace