What is normal flow rate for infloor radiant?

I have recently replaced our old boiler with a 120k btu combi-boiler. The circ pump was also replaced with a Grundfos pump. Our home is 2000sf and we have 5 zones. The combiboiler burns propane. The new boiler seems very efficient, as my propane usage is greatly reduced. But I notice that the circ pump (in autoadapt mode) is only pumping 1gpm if one zone is calling for heat; 2 gpm if 2 zones are running, and so on. I’m a novice, so I’m wondering if that amount of flow is correct/normal? It doesn’t seem like a lot. I’m noticing that the zone farthest from the boiler is not getting very warm (it did before the upgrades). I suspect that by the time the water reaches this zone, it has cooled down. Looking for advice please.