I agree to an extent with some of the things said on here. If you state a day and time for each ‘wave’ to run, you stick absolutely to it. You don’t change it on the hoof just because you’ve sold what you expected to sell in that wave early in that wave’s allotted time.
I expect they knew they were going to sell out and wanted to get it over and done with asap, rather than waiting round for hours at the arse-end of each wave.