Aristo power run graph looks starnge

[Crazybassist]

So a few weeks ago I had my Aristo V300 (full BPU) at a dyno for power runs. The guy running it was struggling with the autobox but eventually figured out how to get a run. Looking at the graph though the top end looks very strange. It dips significantly around 5k rpm, climbs, then dips again before climbing at the end of its revs. Could this be a problem with the engine, autobox, or tyre slip (I thought I could smell burning rubber)? The power figure was 352HP at the crank, which isn't terrible, but I was hoping for ~380HP.

 

The car pulls very well on the road, but does seem to run out of puff a tiny bit towards the higher end of the speedo. I dunno, just looking for opinions on the graph shape really.