Curious if anyone can give me some direction on a unique situation.

Looking to book 4 nights at a Hyatt resort that is showing cheaper on agoda. The Hyatt is having a 3rd night free promotion. If I use the BRG claim would the rate be applied to each night (with the 3rd night showing $0) or will it just reflect in the total and disregard the 3rd night free promotion. I intend to use this in conjunction with the Prestige 4th night free as well. Any experiences?