Howdy is correct.
The Flynn effect, also known as norm obsolescence, is the observation that measured IQs have been rising in the modern IQ test era at a rate of roughly 3 points per decade for individuals near the center of the bell curve, and possibly more for those near the extreme right hand end of the curve, without any apparent increase in real intelligence. In the case of the WPPSI-III and WISC-V, there is a 12 year difference between the age of their norms, which predicts about 4-5 points lower scores on the WISC-V for NT students, and very likely more for high-cognitive students.
Scores at age 4 are unlikely to be highly stable, due to the complexities of testing small people, with their wide range of normal developmental trajectories, unpredictable behavior, high reliance on rapport with examiners to generate optimal performance, and diverse exposure to academics. I doubt that her score will now fall into the average range, but in my experience, it would not be at all strange for it to fall by 10 points.
The WISC-V also measures additional aspects of cognition, which were not captured on the WPPSI-III. These may affect the FSIQ in as-yet unknown ways, especially since you report a historical relative weakness in processing speed (though this was so long ago, and at such a young age, that it may no longer be the case). If comparing WISC-V to WPPSI-III scores is important to you, you will probably want to use the GAI for this purpose. If you are concerned about some kind of learning need interfering with her school and life performance, the WISC-V is a much better instrument for articulating different aspects of cognition. Which, I understand, is your primary interest in this round of assessment.
I would also echo howdy's last comment, which is that new numbers will not change the child you know. The good evaluator interprets test data in the context of the whole child, not the reverse.
