Good idea to swap McIntosh amp stock tubes?

Having experienced a blinking red light issue with a Macintosh amplifier, I replaced the small tubes and for now seems to be fine

I have heard that mac stock tubes are used as part of the design process of the amplifier and the recommendation is not to swap the tubes with something else. The rationale is the amplifiers don't need tube modifications to alter the sound which has already been optimized.  Tube amplifiers that reflect sound changes when tube swapping occurs may not be designed very well. you shouldn't need to change out the tubes to improve sound of your amplifier.

Further because McIntosh amplifiers are so sensitive with all their built-in circuits that sense all kinds of voltage irregularities and power irregularities and tube irregularities, it may be risky to use tubes not designed for the amp.  McIntosh does not support using any tubes other than those that were designed for the amplifier.  

Interested in what people think about swapping out tubes for McIntosh amplifier and I'm talking about small tubes primarily right now. Do you really note changes that enhance the amplifier if you do swap out tubes? Is it a good idea to not use stock tubes?