PMoz99
The standard Ju 87 B was a rather short legged aircraft (P.C.Smith quote a range of 550km for the B-1 and 500 - 595km for the B-2, the latter on the same page in his book! Possibly one data is 'field' data and the other 'factory' data.)
Still quoting Smith the Ju 87 R-1 had a range of 1400km and the R-2 1253km.
I have always understood these figures to be 'ferry' ranges, ie the combat range would then be roughly half, although I think any intelligent pilot would calculate for quite a bit less, meaning the R-1 would be appx 650-680km while the R-2 would come out in the region of 590-620km
Since I presume your range data is a combat one, I wonder what source you are quoting? At least according to Smith his book is 'A Complete History'....
Now, does anyone have the exact route these convoys took? If possible (if I had been in command of a convoy) I would have wanted to be outside the Stuka combat range. Since I am no naval researcher, there might of course have been a myriad of reasons why that would not have been possible, depending on, for example, Winter or Summer conditions, other weather phenomena etc. At least in 1942 the long range of the Ju 87 R must have been pretty well known to the Allies.
Cheers
Stig