The time fuse shell for the 88 actually has a random time until it explodes (within limits) so this means you can get a series of shots with too short or too far explosions and not do any damage to the target.
However, averaged over a few shells, you might do more damage this way compared to the "explode on impact" HE shells, which do zero damage unless you manage to really hit the target.
You just have to decide yourself how good your aiming is. If it´s good, use HE, if it sucks, stick to the time fuse shells to make at least some damage from the nearby explosions.