Do you have access to the old MM wills indexes, some handwritten, which were filmed by the LDS? The Arch ones in particular often had place names within the parish, not transcribed by Brian, but his was a mammoth job making an alphabetical index from these old ones on film which were listed under each parish, each year.

For some unknown reason the Epis indexes to LDS films 0991644 to 0991647 [1679-1697] were not on LDS film, so Brian indexed those from the filmed wills themselves.

In the old Epis indexes on film the two William Corkils (decree and will) were clearly listed under 1676 Maughold along with Margaret Corkill als Creer (will).

But good luck looking at that Epis film, if it is the same one as on LDS no.0991643. I remember it sometimes had two wills (or more) on a page, or a scrawled 1-2 sentence will sideways on the margin, etc., and much of it was black.
Hopefully the MM one is better.

Sue