Heirloom Shards Odds

I have 500+ Apex Packs to open, so I have at least 150 heirloom shards guaranteed, and so my question is: if I start with 0/150 shards and at certain point I get 150/150 shards can I continue the packs opening streak to perhaps reach 300/150 shards or maybe more all in once, or is it better to consume the shards first and then resume to open the packs? is it the same? 300+/150 and 0/150 are the same odds?