R56 MTF Mini Cooper 2010 (Getrag GS6-55BG)

After a gearbox leak repair I need to replace the trans fluid on my manual Mini Cooper non-S 2010 LCI.
I'm searching for a synthetic MTF LT-4 API GL4 75w80 (as required for this gearbox).
There is not any MTF complying BMW MTF LT-4 in my country (South America).
After days of research I could find that local Liqui Moly brand is not selling anymore the TOP TEC MTF 5200 75W80 GL4 (BMW MTF LT-2 & BMW MTF LT-4 specs).

BMW is not selling trans fluid since "you have a lifetime trans fluid"
Other brands (Motul, Castrol, etc) are selling GL4+ (GL4 + GL5) and mineral GL4.

Liqui Moly is calling me to offer the TOP TEC MTF 5100 75W instead of TOP TEC MTF 5200 75W80
TOP TEC MTF 5100 75W is a mineral API GL4 trans fluid with BMW MTF LT-3 spec (but not BMW MTF LT-4)

Anyone can help me about what's the difference between BMW MTF LT-3 and BMW MTF LT-4 specs?
It's related with lifetime and change interval (due a mineral must be changed more often that synthetics) only?
I can't find these BMW MTF LT-n real and exact specs comparisson on the internet