Griff, I agree about Lara's first favor (Gosh, I would like to know what Lara did to win 3 favors. She used her mind, says Mab. And Lara told Eb that she had worked some visas for Mab's people. There is an interesting story there).
The first time I read the book I assumed that Harry has asked Molly for both the suit and the ring but I am currently rereading PT, and when they make the deal, Molly says that she would do "your toy". Singular word. So I don't know.
Perhaps Molly manage to do the suit without incurring in obligation just as government gave policemen uniforms and weapons. It's supposed to be done by the "contractor" not the employee. Instead, a ring would be more like if the employee was paying for an update with their own money. But I may be wrong, it's just a theory.