Well, if we give them the benefit of the doubt, it may be that a number of people were wondering what would be appropriate, so they chose to publish suggestions. Also, the accompanying letter makes it clear that this isn't a "price" or that they are "charging" for the sacraments.
Yeah, they say that, but they won't honor a Mass request unless you pay their stipend ... which turns it into a price, despite their disclaimers. They say you have to invidually approach a priest if you can't pay it and see if you can negotiate a lower price with some other priest. But if you write in to SSPX saying that you don't have the full amount, they make it clear they won't offer a Mass for less. That makes it a price, not a offering ... despite whatever fine-print language they throw on there.
Of course, there has to be some filter, or some people would just go in there and request 100 Masses each year. If I were a priest, depending on the request volume, I would limit it to N number of Masses per 3 months or so ... or whatever.
Another thing we have to keep in mind is that a single Mass is of infinite value. There's technically no difference between having one Mass or 1,000 Masses offered for the same intention, as the single Mass could have the same benefit as 1,000.