I guess that means the Level 5 evos for the captains were crazy. If we assume its a sort of percentage, then since Cole spent I want to say 5 years as a Level 3? and got a 10% boost, then the Captains got damn near double the normal boost for a Level 5 evo. If the pattern holds, that means the simple act of evolving to Level 5 granted them ~40,000 power.
Thinking about this made me want to estimate the total power the Captains have, not counting the Big 3 because they're insane.
MC average power per day as a Level 1: ~0.33
MC average power per day as a Level 2: ~1.1
MC average power per day as a Level 3: ~8.425
Assuming an exponential growth (because this shit ain't linear), line of best fit is given by 0.0212938e^(1.99339x).
This predicts that MC's average power per day as a Level 4 will be ~61.8, and as a Level 5 will be ~453.7.
Let's also assume that each evo's power boost multiplies by 10 each time, so Evo 4 gives 2000 and Evo 5 gives 20000.
Based on the fact Cole got bonus power as a result of being Level 3 for so long, let's also assume that this is also true and a percentage of the total evo power boost. Cole got ~10% extra power for being Level 3 for an estimated 5 years or so.
Estimating the current power of the Captains (not counting the big 3):
Assume each followed MC's growth patterns without any additional boosts or time bonuses up until Evo 4. So while M-Corp is active, each was Evo 4 with a presumed ~3k power. Since then, they remained at Evo 4 for approximately 50 years, before being given the serum and evolving to Evo 5.
High end estimation: Assume MC's growth pattern takes place over the estimated 80 counted days (MC evolved at day 99, and it is currently around day 180). 365/80 * 61.8 = 281.9625 average power gained per year times 50 years is an additional 14,098 power plus the initial 3k gives us an estimate of 17,098 power prior to receiving the serum. If we then assume that you get 10% extra power from your evo for every 5 years you were at that evo, then that results in a doubled evo boost of 40,000, meaning the Captains post serum have approximately 57k power.
Low end estimation: Assume MC's growth pattern takes place over the estimated 1 year (Approximately that's how long the twin + monster world arc has been). That means 61.8 power per year, times 50 gives an additional 3k power. Other assumptions about evo boost due to time hold and the Captains have approximately 46k power post serum.