Old 3" guns have 3 km range, and with newer system flak stops at 3.5, so, it would be incostistent with the AA system.
Removing range bonuses was one of the principle of new AA system, again, to add consistencey, where CV player would know when to expect danger.
It doesn't sound as too big a problem to destroyers, but increasing ranges of Minotaur/Worcester even to 7.6 km can create even huder no-fly zones.
On the other hand, this upgrade could've increased straight DPS, and that can be a topic for discussion.
According to current plans, it would be updated, and after that, if no changes occur, it won't be able to install it on ships withou long-range AA.