1K max. limit is per txn based including bday bonus. Problem with VDC is you can't use more than 50K per day so no one will ever know. It gives 500 Normal + 500 Bonus i.e 1K and then also accelerated of campaign which comes next month. If it had allowed say 75K per day we would have know. Now with physical card we can do 1L per day also but as there is no bonus on it, it will give 1K only which is max.
The VDC 1X+1X are included in 1000 max. per txn but not birthday bonus or accelerated and I can say that looking at campaign points I received yesterday.
With VDC your 50K txn will fetch you 500+500 and if birthday month 1000 for this next month and as accelerated pts are also 1000 max per txn so it will be 3K pts. So better do low txns for max. gain.
Waiting for last month 4X pts to be credited which will clear out more things. Accelerated 4X under 5X campaign is only for Normal points and not VDC bonus. So most you get is 6X or if it is birthday month then 8X.