My son had a spread of 14 points when he took the WISC 1.5 years apart. When we got the low score I had him re-tested with the SB-V and he scored higher than the original WISC-V result by 4 points.
Not knowing your situation, I don't know if it's worth it or not. In my case, I had a lot of evidence that was very suggestive of a higher IQ. But I think the audible timer could have had a significant effect. Frankly, that seems REALLY stupid. How could the tester notice and comment on the distraction the timer was creating, yet keep using it? I would go to someone else.
