One spirit in Weyer's catalogue is absent from the Goetia, and almost nobody has heard of him.
Pruflas, also given as Bufas, stands at number four in the Pseudomonarchia. He is described as a great prince and duke whose seat is around the Tower of Babylon, and twenty-six legions are under him. He is the only spirit on Weyer's list that does not appear in the Lemegeton.
His absence is the other half of the arithmetic that produced the seventy-two. Weyer has sixty-nine. Remove Pruflas and sixty-eight carry over. Add Vassago, Seere, Dantalion and Andromalius and the total is seventy-two. Without the deletion the sum does not work, so the compiler was not simply padding a short list; he was editing it to a target.
Why Pruflas in particular was dropped is not recorded. It may be that a manuscript in the chain lacked the entry. It may be that the compiler had a reason. There is a further complication in the transmission: Reginald Scot's English version, which is the demonstrated ancestor of the Goetia's text, omits the Pruflas entry, so the deletion may have happened one step earlier and not been the Lemegeton compiler's decision at all.
That is a genuinely satisfying detail, because it converts a mystery into a mechanism. If Scot dropped Pruflas, then the Goetia's compiler inherited a sixty-eight-name English list, needed seventy-two, and supplied four. The gap he was filling was one his own source had partly created.
The evidence is good but not complete, and the honest form of the claim is that this is the most economical account of the arithmetic, not a documented decision.