If the meter works okay, do not fiddle or modify this or that because of the heat, dont search for problems that dont exist(s) unless there is.
It was calculated and designed this way ..... you may add problems doing so, do what i said, unsolder it / un screw it from the heatsink, clean the heatsnk compund, put a new layer, re-screw and solder, thats all.
This regulator is for the digital section, aka the displays, the mcu, eeprom etc .... there's a lot of stuff connected to this regulator, do not take a chance to blow something if you modify it, and it doesnt work.
Theses meters only need a recapping over time and they can outlives us in many ways loll