They have the same top-value, but the similarity ends there. There is no way you can describe these models as "roughly the same".
I wasn't describing the damage models as roughly the same but the "raw" damage value itself that is 27> (or 28> in the case of the autogun). And that was my original point concerning damage increments: you can increase the damage of two weapons by a seemingly flat value (for example the autguns/lasguns 13> to 28>/27>) but still make them vastly different with the damage model applied to the increased damage value.