Hello,
In my game I'm playing as the TEC, and I bought both levels of flak upgrades for my hangers. When then first level was complete, it gained an autocannon rating of 40. When the second upgrade was complete, nothing changed - no increase in firepower or range, and the upgrade's text doesn't say what it's supposed to do.
On reflection, 40 flak seems pretty high. Maybe the glitch is with the first level? Maybe it's supposed to go '20 -> 40'?