got it ... a simple example ...

it's 40 degrees, your motor is producing Xbhp at 15psi, it's limit.

the temp goes down to 5 degrees ... your motor, everything else being equal, wants to produce 16psi due to the knock on effect of the increased air density/ mass ... but is limited to 15psi.

it produces more power, cos the charge is cooler, but not as much as it otherwise could, because its limited ...

therefore, the effect of ambient temperatures potentially has less overall effect on blown motors than NA motors which are open to the full effect of the change.