manx spelling at this period was phonetic (apart from the very limited professional/merchant class) and depended on who was doing the writing - a name can be spelled 3 different ways in the same document - place names equally varied (possibly even more so if the scribe had little or no Manx)
The letter/year merely indicates a change in holding passed thru the court in that month (May or Oct court) could be a sale of part, complete disposal or a mortgage of all or part - you need to look at lib vas for reason - these annotations in lib assed were finding aids for the setting quest etc