i am guessing your reffering to a gas( vaporous) system. or are you asking about a different fluid?
flucation will be more about the demand load. especialy if its a load close to the regulators max flow. regulators are rated for minimum and max load size. generally one should size regulator size so that minimum load is higher than 25% of regulator rated , and max load is 7/8 of max rated, this cuts down on hunting of regulator,
and the flucation is the regulator working. and load of demand.
If you cant cool it
HEAT THE Hello out of it