The card’s own bonus is based on spending $1,500 per statement month for the first 4 months to get 25k points for each statement month when you meet that minimum spend (plus std pts at 0.66/$1)
The additional Velocity bonus (30k/250 SCs/Coles voucher, whichever you chose) requires you to hit that spend target in only one month, i.e. you don’t have to make all 4 months, just one month where you meet the spend criteria is enough.
(This is not at all clear in the ts&cs of the Velocity offer, but this has been the experience of multiple people on this thread—many people got the extra bonus after month 1. I got mine after month 2 having opened this card prior to the Velocity offer. As I said upthread, strongly suspect that Velocity do not know when you opened the card—they simply trigger the bonus when a transaction with a specific description/points value hits your Velocity acct—it is also clearly automated as the Velocity bonus posts at the same time as the 25k & std points).
In the case above where you spent $1,200 on first month and $3k+ on month two, I suspect you’d get no bonus on month 1 (just the std pts) and the 25k + std points + your selected Velocity bonus on month 2.