As long as you have at least 1 full set of BPs, the first 10 levels can be built with that 1 set. Any BPs above that first set will still be available once you build it. So, if you have 8 sets, you will have 7 sets available when you level it the first 10 levels, plus any you may have acquired while getting it to 10. After the first 10 levels, you will need a full set per level.