Thanks, Averil. That second marriage explains the dates. I had a quick look at Tom Corteen's Maughold parish register transcripts (which are the burials used by the FHS) and there are just a few variations which you might like to use, for accuracy.
(All Maughold.)
The burial date for Jam: QUILLEASE is actually Mar 15 1677/78.
John Looney & Margery Woods married 16 April 1666.
Margery WOODES was buried Mar 6 1687/88.
The burial entry has: Anne QUILLEASE ali Costen buried Jan 22 1720/21.
(The FHS has added the duplication for indexing purposes.)

Sue