I don't know about the 200 or 300, but on 600 you can change the response from the standard 600 ms and see if it works for you.
However, what you describe is prefectly normal. If you tell the remote that you are presisng the key 10 times, it will follow, by sending 10 of those commands. I think if you reduce the lag time to 100 ms, it will just send them out faster. I could be wrong, though.
I tried setting it to 100 and 0 ms, but it seems the minimum that the remote can do is about 500ms. My dumb remote can go faster than that. Once you get used to it and the device, you will learn the response rate and press it at just the right moment to make it go as fast as it can go.