I have had two children sit both Wechsler tests and SBV and both of mine were far stronger on the SB5 NV section than the Wechsler PRI scales. Both of them struggled with any of the cartoon based subtests on the Wechsler tests. No idea why. So your DD may have had much stronger results on the SB5 NV section than she did on the Wechsler. The SB5 also does not test for speed really at all, while the coding test on the WPPSI is as much of a test of good behaviour as it is speed for some 4yr olds. My DD did it at 4yrs9mths, did each item twice (perfectly) in half the available time and watched the clock for the second half. She scored 10...
None of this tells you much about your DD, but it certainly is possible to get quite a difference between the two tests.
