Unless you are using ACTIVE crossover for the bottom end vs. passive components in the speaker than I would guess this could be slightly true, only because if you Verticle(or standard) Biamp one power supply this will split it equal between the 2 channels on the board, so bass will always be far more demanding on the one channel used for the bottom end and you only have 50% of the reserve available, Bass will take up about 60-70% in general I would say so then you could limit it vs. Letting it run in mono and get the same sound thru the system, but you will only ever really saturate maybe 20-30% of the power supply on the mids or highs at any time, and you will have that extra 60-70% still available on tap for demanding low's if in mono mode..
Now this may not be true with all designs, such as if you have a DUAL mono Stereo amp it means it has a torroid transformer on each channel so you would be okay either way, Also never ever take any of these types of Theory's or Number's as correct to what will sound better, cause I say you must try both ways and actually hear and experiance it, cause certain speakers will react differently as well, I am currently using monblocks myself, but am going into an upgrade to add the second power supply and have configured for stereo to verticle bi-amp, but in my case this is necessary cause I am running A parametric EQ for my bottom end and must have the seperated channel to do it, and this should prove superior to any mono block feed the whole speaker, because active biamping is far more effective than Passive(crossover) biamping.
Another scenario possible with biamp over mono is that you want the extra outputs for running two totally different speaker cables to experiment which works best in combination feeding the upper and lower end, but this is almost silly but could be effective I guess.
Now this may not be true with all designs, such as if you have a DUAL mono Stereo amp it means it has a torroid transformer on each channel so you would be okay either way, Also never ever take any of these types of Theory's or Number's as correct to what will sound better, cause I say you must try both ways and actually hear and experiance it, cause certain speakers will react differently as well, I am currently using monblocks myself, but am going into an upgrade to add the second power supply and have configured for stereo to verticle bi-amp, but in my case this is necessary cause I am running A parametric EQ for my bottom end and must have the seperated channel to do it, and this should prove superior to any mono block feed the whole speaker, because active biamping is far more effective than Passive(crossover) biamping.
Another scenario possible with biamp over mono is that you want the extra outputs for running two totally different speaker cables to experiment which works best in combination feeding the upper and lower end, but this is almost silly but could be effective I guess.