Where to install the 'T'

I purchased a coolant filter for my 6.4. The instructions say to insert the 'T' fitting into the heater hose on the passenger side which is before the heater core.

A while ago, I purchased the DieselSite cold rush valve that shuts off the coolant flow through the heater core which is suppose to give you colder A/C. The valve is inserted in the heater hose on the drivers side which is after the heater core.

Since I already have a cut in the heater hose for the valve, I thought about removing the valve and inserting the 'T' in its place.

Is there any reason why I can't insert the 'T' fitting in the heater hose on the drivers side which is after the heater core?

TIA