SPs only think about money, i don't know any SP around here that would give you an extra free shot unless she really likes you or smitten with your equipment. And unless you are some kind of wonderstud 2 shots/1 hr need to be planned ahead, you need to blow quickly in the first 15 min so you can rest enough to do it at the end, at which point she will likely tell you it's an extra Xx $
On a side note, these acronyms like MSOG (when it's always just 2 shots and every single shot is charged) And YMMV (i.e. special treatment) really annoy me and obscure what should be plain and simply written.
Next time I'm at Starbucks I'll ask for 'multiple shots in my cup', and when they are confused and ask me how many is that, I'll say 'how much mileage will you give me"