the film numbering is indeed different but as they are both the same films (apart from some early films) there should be a 1:1 mapping between LDS + MM numbers - Brian worked from the LDS description which gives years but sometimes book1 and book2 of the same year are split between films - for some years there are book1A wills but when you get to read the actual films the nominally seperate book1 and book1A are intermingled - in some years book2 and book1 are in the reverse order on the film.
Any new wills I find are always entered into my summary files on Manxnotebook