4amp Fast Charger for Revel Drive Batteries!

I wasn't impressed by Revel's 3a 'fast' charger vs the stock 2a one, was surprised to find my recently purchased 4a charger (for a 10ah Verreal F1) was perfectly compatible.
Just to be clear, consulted with an electrician friend and others on forums, one couldn't find any reason why it wouldn't work, the other claimed these battery cells can even handle 6amp!
I got 65-70mins to fully charge (from the 25% voltage warning on my remote point) on my 4ah battery with the 4a charger, and 105-110mins with the larger 6ah battery pack.
However, I'm not convinced Revel's timescale claims are accurate with their 3a charger on a 6ah battery pack; instead of 120mins I'm thinking 130-150mins is more likely! (Genuinely, eager to compare with other people's results...)