In principle modular charges are the way to go. However, there's often a divergence between theory and what gets deployed. There is of course a choice of 155mm modular charge designs, and very few armies have conducted comparative trials, etc, before selecting one for service. There's some evidence to suggest that a single charge family won't work in practice. For example the UK conducted a shoot off and analysis between US, UK, GE and SA designes. They eventualy selected the SA (Somchem) design despite being unable to get satisfactory license production arrangements. This design actually is not truly modular because Somchem found that they had to use a bimodular design, basically a 'green bag' set and a 'white bag' set. Of course the Brits then shot themselves in the foot by decreeing that all future ammo, including the newly selected modular charges had to meet insensitive ammo requirments, this required some re-design of the Somchem design and they still haven't been able to type classify the insensitive version, which has put the 52 cal barrel program into abeyance! The big attraction of the Somchem design is that it has far lower barrel wear than other types (and they don't even use chrome plated barrels) and much longer EFC life, this is achieved by a design that puts cooler gas into contact with the chamber and barrel walls. Clever if they can get the insensitive to work.