They're valuable people to the band just as Aki-sama is to Acid Black Cherry,even if they're not always apart of the band, they involvement is an important asset.
yeah they may not be included all of the time, but when they are we are fully aware of their presance in the band and the key roles they play.
Personally, i'd feel bad if I thought of an accepted Akihide being Acid Black Cherry's support but ignored Makotsu's existance within BREAKERZ.
I think of BREAKERZ as being DAIGO SHINPEI AKIHIDE
skull-chan and when Makotsu are involved then I think of BREAKERZ as being DAIGO SHINPEI AKIHIDE MAKOTO MATSU
skull-chan.
Same goes for Acid Black Cherry, ABC will consist of AKIHIDE, SHUSE & MAKOTO etc only when they are involved.
Because at those times, they become the bands formation, a band is not a band unless it envolves all the parts that form it. ~ except those one man bands where the guy has all the instruments strapped to him :S
BREAKERZ would sound very different if it was just DxAxS playing their instruments.
I do realise and recognise when a singer performs and has a backing band etc to provide the other parts but those people can be anyone at the end of the day, to me it just feels different as these people were selected and are regularly used.
For example, I wouldn't consider it a band if it was Ayumi singing with Akihide, Shinpei, Makoto and Matsu providing the music because its just Ayumi singing her song with some random guys providing the music, if however these guys were always being used then i'd think of them as her backing band since Ayumi is a solo artist and they're never known by a band name nor as the support members of that group. This case would just be like when you see Johnny's perfroming (e.g Kanjani8) and there will be Five(or any other) as their backing band.
If any of that paragraph makes sense
Makotsu are down as Support members, I therfore consider them to be the supporting members at the times they are used.
Its fine if other people want to think of BREAKERZ as being DAIGO
never true and i hate you for this 
or if they want to think of BREAKERZ as being DAIGO AKIHIDE SHINPEI
afterall everyone is entitled to their own opinion.
To me they'll always be DxAxS and DxAxSxMakotsu when they're included
maybe i'm wrong