1A or 1.5A or whatever, that's not a 'target.' That's an 'absolute maximum.' Meaning above that rating all bets -may- be off.
How close you want to push up to that rating depends on whether you want to 'bet the farm' on it or not.
If you're out 2.5km and a sudden downdraft causes the motors to SURGE past the limits to hold a flight path, voltage may drop, systems may reset, and depending on what failsafes are set to and whether it can recover fast enough will determine if the flight continues or the aircraft drops in a lake.
For SAFETY purposes, use an amp rating that is twice the maximum likely needed.
Under race conditions in a relatively close space where a couple of grams add a bit of agility it may certainly be worth the risk.
For PERFORMANCES purposes, by all means push the envelope.