> > I would have thought this would be: > > > > 1) correction issued as table > > 2) correction issued as formula > > I think that's an orthogonal category called "corrections". Updates > to the table or formula can still occur on either a fixed or as- > needed schedule.
There are some fundamental differences here. Looking at leap years, the formula that we have could produce a table. The table could be tweaked at various points to optimize things over the short term to be better. However, the formula that covers over 10k years is better because it doesn't have to change, even if we have short term variations that might be optimized away if we dropped this day a little early or late. So to chose a formula might mean that we accept a slightly larger UT1-UTC offset at times, but do so in the same of the long term average and simplicity of implementation. There is an implicit assumption in this argument, however, that a table would be necessarily more complicated than a formula for leap seconds, I guess. Warner
