There might be an internal protection not to allow max amp draw for too long, because it assumes there's a stall. Or, there might be thermal overheat protection. I'd guess the former. Some of the scooters have weird regulation mechanisms.
Don't take my word here though, I hope someone with actual experience with your controller can give feedback.
New to endless-sphere? Notice a lot of signatures recommending Ebike.ca? That's because it's the best place for a quality and manageable, (but still 'real'), first build. Justin is a solid supporter of electric bike development, and a good source of equipment.
My hat off a thousand times to the green people that effectively run this forum. The ES Mods are superb.