if she doesn't explain it herself. It could be any of the scenarios you mentioned, or maybe the upgrade is for Greek, or it could be something completely different. It is not up to you to assume what it means.
First, are you sure there is no explanation on the website?

I have seen it where it is listed something like this:

           Incall/outcall

1 hr.      400/500
90 min   xxx/yyy
2 hour    aaa/bbb

Sometimes depending on your browser (especially if you are on a phone or tablet and the website wasn't set up for mobile, the format is thrown out of whack, so lines don't line up. You might get something like this:

Donations                      incall/
Outcall
400/500   Xxx/yyy

Double check that you didn't miss something and that the format is not out of whack. If not, then you will have to clarify with her (or just move on to someone else whose rates are clearer) As I said earlier, don't make an assumption based on something someone here says it might mean.

Could be any of the above.  I'd ask her thru whatever communication she asks for.  There is no sense in going further with her until you know exactly what she means.

LLAP,
Swim

If so, it could represent her donation in terms of US and Canadian dollars.

I would assume incall/outcall but I would ask her. I find it odd that her ad / website wouldn't specify.