The truck does need to come a bit later but not 90s. And Kronosaurus is right for wanting the option for early truck set-down.
Imagine if someone was asking for Soviet T1/T2 to be buildable only after 90s. And you said "no, I want options" and somebody shouted at you "ermahgerd, you no like decisions and conserquernces!?"
C'mon...
Will it be enlightening to you if I say you that soviet T1/T2 WERE being build for 90sec-120sec for 6 months?
Make the truck as slow as coh1 brit trucks(enough mobility to get where it needs to go, not enough for it to have any relevant combat use), keep it free but make it buildable from HQ for X amount of time so it doesn't arrive instantly but still forces you to choose-more units or fast tech, make it arrive after 90 sec.
The ideas are many and its not like OKW starts with enough fuel to instantly get the truck going, so we have even LESS of a reason to keep the first one arriving so early.
As it is now its simply a free unit with limited, but still meaningful combat potency that can take down inconvenient garrisons and push infantry out of cover for kubel/pios/volks to pick off.