[Al Skierkiewicz]

In the past the rule...
<R48> The ES17-12 shall only be charged between MATCHES by a 6-ampere rated automatic
battery charger. When recharging the Kit Of Parts batteries, either the charger provided by
FIRST or an automatic charger with an equivalent charging current rating may be used.

has been interpreted as to allow the lesser current. First provided 4 amp chargers many years ago when we first started using the 12 volt gel cell batteries. If you are concerned, please ask the Q&A. Yes we are stressing the batteries at the load we place on them, but it is for only two minutes. A high current charger left on for several hours is likely to produce excessive heat in the battery which can produce some nasty venting of gas and damage to the internal assembly.
Yes, I have seen teams bring in fifty amp chargers and hook them up with aligator clips in the pit. I hate the smell of sulpheric acid and burning plastic in the morning.