Increasing range increment of Underwater Demolition bomb in water – is it possible?

[Natural 1s]

If alchemist has feat Underwater Demolition – is it possible to prolong the range increment of bomb traveling through water?

Pathfinder Roleplaying Game Advanced Race Guide wrote:

If the bomb travels through water, the range increment is reduced to 5 feet.

Should it be reduced after all bonuses or before?

possible bonuses:

Longshot: +10 feet (untyped)
Bomber’s Eye: +10 feet (untyped)
Bombchucker: +10 feet (untyped)
Strong Arm, Supple Wrist: +10 feet (untyped)
Bomb Launcher: increasing to 30 feet (70 for rocket bomb)

[Natural 1s]

Is there anobody else who finds it confusing and would like to know correct answer?