Hey Dark.Revenant, love your work man.
I gotta ask, is the Excelsior-class Phase Corvette in the current version meant to have -1250 for its cloak upkeep cost?
With the "Duel of the Century" mission, I get that using the Phase Shunt on asteroids and incoming munitions is a viable way of building up flux to charge the cannons, but as it stands, the limited number of charges for the shunt, coupled with the negative cloak upkeep cost, makes it near-impossible to accumulate flux fast enough to maintain survivability (let alone lethality), especially against nimble opponents with weapons that can one-shot you the instant they manage to phase-skim or teleport behind you.
I can understand if Fabrique Orbitale's poor attempts at reproducing an unorthodox phase/flux system is your way of balancing an otherwise overpowered ship, but together with the poor peak performance time and deployment/maintenance costs, I doubt the Excelsior would find a place in anyone's fleet outside of the mission.