Behavior difference observed for SAP NW7.3 (As ABAP) for ROMS/LOMS

Hi

For new SAPNW7.3 as ABAP,

For LOMS configuration,if we select Polling and come back to ROMS and try to select callback and unselect Polling it asks "You must adjust the logical OMS.Do you want to continue.

It does not allow to select callback and unselect polling and save the ROMS.

But for earlier SAP7.0 as ABAP,

For LOMS configuration, if we select Polling and come back to ROMS and try to select callback and unselect Polling it asks,"You must adjust the logical OMS.Do you want to continue."

But it allows to select callback and unselect polling and save ROMS.

I see this behavior in these 2 versions of SAP NW.Is it expected bahavior.Any pointers will be helpful.

Regards

Anjana