Can APN-AMBR limit the througput?

In a scenario where two operators are sharing the same RAN infrastructure with basically all the same parameters and configurations (same bandwidth, same frequency band, same carrier aggregation config same QCIs, etc), can a different value of APN-AMBR (in one case we have more than 4Gbps and on the other we have 256Mbps) be the reason why we have a considerable difference of throughput?

APN-AMBR is stored in HSS to indicate max bit rate of all non-GBR bearers on that APN.
For one APN, UE may have 1 default bearer and many dedicated bearers.
The APN-AMBR is sent from MME to gnb in “initial context setup request” which limit rate of UE connected to the specific APN, so in this case it may be the reason of major difference in DL throughput.