Certainly flooded batteries can and do last as long as an AGM in some cases, perhaps longer than an AGM occasionally. But in general, as a segment, AGM are considered to be the superior choice with longer life, no topping of fluids (important for some difficult to access locations) and better response to an occasional discharge, which can often times permanently lower a flooded battery's capacity and life. This situation for the OP is unique where the AGM is of lower capacity...that is odd and unusual and may cause me to reconsider, unless I could find another brand AGM of equal or superior specification. But if the AGM meets the Ford Explorer requirements, then it may be just fine.
I've personally had an oem Toyota flooded battery go 14+ years. I replaced it with another flooded. But in all my other cars I have AGMs for the reasons stated above.