Originally Posted by
dszrew
what I'd likely do is put $5,000 on the Reserve card to get the mile bonus, then try to hit $25,000 on the platinum for that level bonus. unless I decide there's a chance to get up to $30,000 on the reserve card. but I'm a third of the way there on the Platinum and not sure I'll spend $30,000 more this year.
MQD from different cards combine to a single MQD counter you see on the Delta website.
Spending towards MQM bonuses from different cards do not combine. What you can do is convert your Platinum to a Reserve and the spending will not reset according to anecdotal evidence here on FT and you can then hit $30k on the Reserve and get the higher MQM bonus for Reserve.