Well here are the things ive tried so far:
I tried to add the Values to default Openxcom item rulesets, I tried it with the Final Mod Pack rulesets, and I tried it with a mod that is a custom version of the default Handgrenade, however I still always get the default 50% tu and 25% tu for priming/throwing. But I am using OXCE tho, I can even use other ruleset values exclusive for OXCE like Craft shields, armor and also the flat- modifiers for Items, except every Item that has the Battletype 4-5