Paypal Masspay CAN be used for anything.
When it came to a particular purchase, I was requested to pay via paypal masspay. I happily obliged, and saved my seller around $50. I was curious. I decided to phone.

After going through paypals ridiculous automated system I clicked 3. Yes, of course I would like to speak to an operator! Paypals website has details as to how masspay works but does not actually state who is, and is not allowed to use it (at least definitively). I proceeded to ask.

My question was met with an extremely polite, “I am sorry, I do not know. Will you hold“. I did. I waited, and a response came back saying yes it is absolutely fine, anyone can use it.
The staff member however suggested masspay had different fees than those documented, and seen by those who have used it. I re-asked my previous question, and asked for clarification. After a labouress process, and multiple periods on hold I was happy with the response. Masspay definately can be used for anything, and you are well within your right to request payment be sent via masspay for absolutely anything.

On ebay, payment can be rendered by normal paypal, cheque, postal order, bankers draft, and yes masspay. This has come from the horses mouth: paypal staff.

Clarification however I feel is neccesary here. You are allowed to request payment be sent by masspay, however you are under NO circumstances allowed to request masspay payment for the purposes of saving on fees. This may be a by-product of such a payment, but paypal Terms of Service clearly state that you can not request the buyer absorb their fees.

The only other slight thing is that you need a premier, or business account to utilize masspay.

I would at this point like to point out, paypal provides the masspay feature as a tool. I use it because it makes the large number of transactions I complete easier to manage, and log.
If every Jack, and Jill uses paypal to buy their Christmas presents on ebay for $20 each, then paypal are well within their right to remove this feature. Dont ruin it for the legitimate users by abusing it !

Best of luck with your business transactions.