Distance should be exponential, double the distance, quarter the damage. This is not stated in the rules, but that is how explosive force works and also makes it easy. The book example is linear which will result in a much larger blast radius compared to the real life numbers. Not a huge deal with small charges, but quickly unmanagable on large ones.

Book example 2yd 5d6, 3yd 4d6, 4yd 3d6, 5yd 2d6 6 yd 1d6 vs 2yd 5d6, 4 yd 1d6.

Taking a Mk3A2 offensive (aka concussion) grenade which holds 1/2 lb of TNT (roughly equal to 1 stick of dynamite) in a non fragmenting fiberboard case. It is listed as having an effective casualty radius of 2 meters in the open (closed spaces increase blast damage). Following the 5d6 for 1 stick of dynamite, exactly following the rules would still have the blast be equal to a rifle shot at 6 yds, while the formula I list has it doing 1d6 at 4 yds (still double the listed effective radius).

So accepting the 12 stick example numbers are correct, you would get 2yd 21d6, 4yd 5d6, 8yd 3d6, 16yd 1d6 following the 1/4 damage for each doubling of range, while the book example would be doing damage out to 21 yds, losing 1d per yard (not sure where the poster above got the drop by 4d6 per yard).

A 500lb aircraft bomb (approximately 200lbs of explosive filler or 400 sticks of dynamite, not even going to do the math) has an explosive blast radius of 13 meters, with effective fragmentation to 40+ meters. -1d6 per yard would greatly exceed both the blast and fragmentation given by the military.