I hope I understood it correctly if not please correct me if I am wrong.

Yes there is a minimum limit for a bonus/promotion. That is 0.05 BTC for your first deposit to give you of 100%. Your second and third deposit of the same minimum amount of 0.05 BTC gives you a 50% bonus each. Do keep in mind that there are cashout restrictions while the bonus requirements aren't fullfilled AND there is a maximum bet rule for the period you are working on the bonus requirement which is betting a max amount of 0.05 BTC

Incase this wasn't your question please elaborate it a bit more if possible