Date Driven Global Constants

Global Constants are a great concept but I had hoped that when I saw the start/expiry date fields these would drive constant selection. Eg a tax rate STD_IT changes from 20% to 19% on 1 July 2018 so I enter 30 June 2018 as the expiry date on the existing constant STD_IT create a clone with the start date 1 July 2018 and tell Ragic on the appropriate sheet which date field drives the constant selection. It seems the date fields are purely for info, unless I’m missing something? Also, it isn’t possible to re-use the constant name, which would be necessary albeit with some validation to make sure the dates don’t overlap.

I did try to set up my own table ‘Rates’ but in order to use this data there must be a field common to both sheets and that makes it unworkable as there could literally be k’s of records referencing the rates.

Could Global Constants be improved to facilitate this?