"Please explain "a CEP of 1.000 m".
CEP = Circular Error Probability = the radius of a circle around the aiming point within which a given percentage of the bombs/missiles/whatever will fall (usually 50%).
"The GAF, however, had the means of going in vertically with the Ju-87"
Actually, they may not have done. As photos show, the Ju 87s of the
Nachschlachtgruppen frequently had their dive brakes removed (albeit not always). Their night attacks were generally conducted in level flight or a shallow dive - I'd imagine vertical dives at night are not a good idea - and so the brakes were just extra weight and drag.