After a 30 year career with my employer in Sales and receiving Good performance evaluations, I was terminated with no warning and no reasons

As a general matter, your employer need not provide you with any severance. Many employers offer severance payments because they are coupled with a general release from the employee, and the release is what they are after -- so that you do not sue them for age discrimination. Often, the first offer is just that -- a first offer. The best way to get the offer improved upon, if indeed that is possible at all, is to have an attorney call your employer and reject the offer and give them a counterproposal. Having an attorney call signals that you "mean business" and your employer will understand the implied threat. Good luck with it.