Yes, it's stated right on the instruction/terms page or card that comes with the "booklet" when the GA gives you the VDB vouchers. ("Booklet" in quotes because it's not always an actual booklet, sometimes separate sheets depending on what kind of printer that gate has.)
Think of the vouchers as coupons that are part of one ticket. In a way, that's almost what they are - they have the same numbering as do tickets, with coupons 1, 2, 3, 4. I haven't gotten more than $400 at a time, so I don't know if they can go beyond coupon 4 or if a new sequence needs to be started.
You can use some, or all of the coupons you get in one bump voucher set to buy one ticket. You just can't combine coupons from different sets towards the same one ticket. AFAIK that's always been how it works. In part probably to prevent people from buying expensive tickets totally with vouchers.
BTW for the OP, your status code for Premier Exec and Premier are "1P" and "2P", not "P1" and "P2"
Oh and welcome to Flyertalk! May you get many more vouchers - it's still a good deal even if you can't make the big score all on one ticket.