Ohio Rule 3770:1-9-250 section 14 explains the MegaMillions cap this way.
(14) - As based on pool sales, should total prize liabilities for the prize levels described in paragraphs (D)(1) through (D)(8) of this rule exceed the liability cap agreed upon by the directors, then that liability cap may be enforced for the payment of the prize awards set forth in paragraphs (D)(5) through (D)(8) of this rule. In the event the liability cap is exceeded, then the prizes set forth in paragraphs (D)(5) through (D)(8) of this rule shall be paid on a pari-mutuel rather than fixed prize basis, provided, however, that in no event shall the pari-mutuel prizes be greater than the applicable fixed prizes. The amount to be used for allocation of such pari-mutuel prizes shall be the liability cap less the amount paid for the grand prize jackpot and any of the four lowest tiered prizes as set forth in paragraphs (D)(1) through (D)(4) of this rule. The Ohio director shall make the amount of the liability cap available to the public via the Ohio lottery website and any other means that the Ohio director deems appropriate.
Apparently the four lower levels 2+1=$10, 3+0=$7, 1+1=$3 and 0+1=$2 are fixed and everything else is adjustable in Ohio. Other States have their own rules for example,California has pari-mutuel prizes for all levels so your actually winnings will depend on the State in which you play.
RJOh
P.S. I could not find the amount of that prize cap posted anywhere.