.FLAT file "duplication"

Christian,I'm 'studying' the development of your generated scenery files (in case I ever need to modify just a small area without having to delete a complete region of the world).Two questions with hopfully simple answers:(A)I can locate lat/lon of created .FLAT files but I am currently mystified by the significance of the seasonal variations at the end of the file name; do they mean perhaps differing resolutions of the same geography?These are examples: (positioned in the Gulf of Oman, just south of Iranian coast)0131333111LM.FLAT0131333111SP.FLAT0131333111SU.FLAT(B)Is there any significance to the seemingly fixed and commonly occurring sizes of the .BMP files (2K, 6K, 22K, 86K and 342K) that I see other than the density of the imagery in that area?Thanks for your interest and dedication; you are much appreciated.LoydRecommending a 'visit' to Glacier National Park (on Montana-Canadian border)...