I wonder if it's just an issue of misplaced decimals in the hover-over. It looks like weapon fire rate should be progressing 0%/5%/10%/15%, so maybe behind the scenes it's actually 10.3%. Likewise, assault action critical chance is likely either 0%/1%/2%/3% or 0%/10%/20%/30%, rather than the 0%/10%/2%/3% that shows up. Bravery, too, considering Angelisar's Fungal Parasite attribute gives ships built in the sector 5/10/15 Bravery, is probably a 0/1/3/6 bonus rather than 0/0.01/0.02/0.06.
EDIT: Comparing the Bravery listings for my fleets of the same faction (ones that weren't made in the Scarus sector), I think I can confirm that Bravery progression from ship level is actually 0/1/3/6. Assault action crit is harder to check because of Death World bonuses. I did compare the stats for level 3 ships and freshly made level 1s, and the level 3s had 90% of the latters' Reload Times, so I believe it is actually the 10% bonus I figured it was.
tl;dr I think the hover-over for ship level bonuses just displays the wrong values.