Unit of measurement changes sure are a headache, and probably part of the issue.
The machines we have are metric, though we're an inch based shop. So our feed rates are in meters per minute.
So for us, running something routinely "fast" is a setting of 15 m/min, which is 590ipm. A cut is too fast, well you drop it down by increments of 1, about 39ipm per adjustment. A "slow" cut is 5 m/min, or 196ipm. The slowest we ever go is all the way down to 1 m/min, which is 39ipm. Generally that's avoided at all costs, we've set material on fire at that feed rate. But that's all the precision of feed adjustment we ever needed. Wood just isn't that picky.
On this job I went all the way down to .5 m/min (19.68ipm), and we weren't even sure the machine would accept it in the settings.
So managing to go up to 54ipm sure sounds like a big increase in feed rate, but on our machines that's a feed setting of just 1.37
We're just not used to that small of change having an effect. Kind of a weird feeling.