Congratulations!!! You get the first incentive in this year.
This year accumulate sum is 55 sets included this order.
So we will ship you 21 sets included the incentive unit(1 set).
You asked me about payment term.
It is our company policy so I can not change by myself and my boss also.
But I give you two options, the first one is same as by T/T in advance 100%.
The second option is by 60 days LC usance after shipment date.
I hope that you can satisfy with it.
FYI, Incentive policy for SD Tantavade