Monitoring happens with Cakewalk driven rate, by default every ~75 ms (can be changed in Cakewalk preferences).
"Ultra" means monitor every cycle, so every 75ms. Other options skip some cycles.
Some devices are slow and not able update feedback (especially display) so fast. For such cases there is "Min. cycles" option. So, it monitors with desired rate but once trigger (monitoring condition is changed) it ways specified number of cycles.
Note the "Priority" is unrelated to the rate, it instruct in which order monitors should be checked within one cycle (f.e. monitor which detects current strip type, track or bus, should have higher priority then monitoring current strip volume)