Correct, gordonbrittas. That's why I advocate the keep it simple programming philosophy. Enter just the bare minimum, and go from there once you have problems.
In addition to what TroyMail said, the more data programmed and the more entries (i.e. if you have 10 different TGs for the same frequency), the slower the scanner will work. If it is checking for an entire frequency once instead of a specific group of a frequency 10 time, it would more rapidly acquire voice traffic. I assume, on the margin, additional data for the radio CPU to process slows things down too.