Complainant wants to submit additional evidence – always a good idea to respond?

Hi,

So I'm basically in the middle of a UDRP dispute and I'm defending it myself. Suddenly over a week after I submit my response on deadline, the Complainant suddenly asks the case coordinator if he can add additional evidence, regarding a small email communication we had while the UDRP dispute was ongoing – this was also over a week after the email exchange took place.

I'm of the opinion that not really sure the email exchange would really help the Complainant's case, and I'm actually…

Complainant wants to submit additional evidence – always a good idea to respond?