WHY Oil parameter indications (Quantity, P & T) are always grouped together!?

OIL SYSTEM INDICATORS
These relate to the oil parameter indications. These
indications are essential to the health of the engine.
The oil system parameter indications are grouped together, this
is for two reasons:-
* ease of reading,
*simple to compare one engine indication to the
other. This can sometimes give an impending
fault indication.
The oil pressure indicator has a dial normally calibrated in
pounds per square inch (psi). The indicator may have max.
limit markers, but will always show the minimum pressure that
the engine is allowed to run at. The reason that some engines
have an upper limit is dependent upon the type of oil supply
system. Some systems may be regulated, therefore needing an
upper limit, or be based upon flow where an upper limit is not
required.