for one

in Oklahoma City, the ryder truck was parked inside the garage beneath the buillding. in Nashville, the truck was not inside any of the buildings.
what type and how many explosives used would also factor in. the direction of the blast. was it designed to go straight up? did it blast in all directions? the energy expelled in the blast could be concentrated into one area causing maximal damage to structures or it can dissipate expelling into many directions at once, causing less damage but to a larger area. not all explosions are the same.
like a shotgun blast. a shotgun using shells full of pellets, at close range can cause alot of destruction because the pellets are concentrated in a small area. but at greater distances the pellets will spread out hitting a wider area but causing much less damage.
just like demolition crews, when they use explosives to bring down buildings. it can be done perfectly, where the building falls in on itself, but one slight miscalculation can change the outcome drastically.
not hard to figure out, i have no training in explosives, but just can think critically. i would suggest trying it and stay away from conspiratorial thinking without evidence.