An Impy is physically limited so can't fire at 20bps I believe. I think it's something like 13.6 for the old board but the cricket might be different - Nick?
Plus, the stock board on an Timmy is limited to 14bps, so unless they have a semi-only board (of which I have only seen my own in the UK) you can't fire faster than 14bps whatever you do. who's was it? and what hopper were they using?
I would suggest that Sparklies chrono was mistaken mate
ROF is important, as long as it doesn't come at the sacrifice of playing tight. Get both together and you're rocking.