Is there a specific reason that the maximum reveive size is different on CAS and MBX by default?

Hello,

we get errors in SCOM The Ehlo options for the client proxy target did not match while setting up proxy for user on inbound session. The critical non-matching options were maxSize. I found a solution on the web to set the Hub and Frontent Transport size to the same value. 

I just want to get sure that i do the right thing. So i want to know if there is a specific reason that the Client Frontend Transport size is set to 35MB and the Default Frontend Transport size is set to 36MB by default.

Thanks in advance for your reply.

BR

Hubert