so i would like to know if you can tell me how to calculate the Hi, Lo channel numbers
It looks like W2SJW provided all the data you seek however here is the rule of thumb for calculating those low/high values for
Motorola UHF systems.
It won't work for APCO systems and doesn't apply to EDACS and LTR.
ChLo for a particular table entry will equal the offset value. Often (but not necessarily) this is 380 for the first table entry.
ChHi for a particular table entry will be one less than the next higher offset value. Using Somerset as an example, the first entry's ChHi is 430-1 or 429, since 430 is the next higher offset. The second entry's ChHi is 450-1 or 449. The last entry's ChHi, where there is no higher offset, will be 759.
If there is only one base/offset/step entry in the configuration then the ChLo will equal the offset (usually 380) and the ChHi will be 759.
Note that this is a rule of thumb. It will not always work and I won't complicate things by trying to explain all the unusual circumstances when it wouldn't work, but this would be the first thing to try for a new system where the data isn't in the database. (Or post a query here, a bunch of people would be happy to help.)
Jim