According to the sfz v1.0 spec,
count is used to define the number of times a sample will retrigger, start to finish, sans envelope generators, before ending. The spec says the sample playback mode will automatically switch to
one_shot if a value
count is specified.
AFAIK,
loop_count was introduced sometime after v1.0 but I'm not in a position to check my “sfz Data Bank†or trial & error it in a sfz app. Maybe on Sunday, the day of rest.
Search the forum: René dropped a whole swag of new loop opcodes back at the end of last year.