"The EHT has made duplicate calculations in most AD1400 situations of PCs without using series extended to 1980. (As I noted in a post, in MM03, we noted that many of the series had been extended to 1980, but it???s not a point that we dwelled on and I???m pretty sure that we subsequently said that this was not an issue that we were particularly fussed about.) Nonetheless, the EHT have re-done all" . . . .