Valid time for rates

Hello
This is a feature suggestion.

Would be great to have the "valid from / effective from" field in a termination rates. Usually termination providers sending the rate updates often and there updates usually have a date when the rates becomes valid. Currently if we have 4-6 providers, every sends the updates at least once a week, we will need almost every night manually replace the termination rates, much better will be to import new rates upon reception but with the field in the database when these rates will overwrite previous from a same carrier.