I knew the way it was being described didn't sound right, your interpretation makes a lot more sense.
Definition of "Common Equity Interest" (emphasis mine) from proposed confirmation order
"1.73 Common Equity Interest: Collectively, (a) an Equity Interest represented by the 3,000,000,000 authorized shares of common stock of WMI, including, without limitation, one of the 1,704,958,913 shares of common stock of WMI issued and outstanding as of the Petition Date, or any interest or right to convert into such an Equity Interest or acquire any Equity Interest of WMI that was in existence immediately prior to or on the Petition Date or (b) a Claim, other than with respect to the Dime Warrants, which pursuant to a Final Order, has been subordinated to the level of Equity Interest in accordance with section 510 of the Bankruptcy Code or otherwise and whose shall count, for purposes of calculating Pro Rata Share of distributions, shall be determined by dividing the amount of an Allowed Claim by the per share price of WMI common stock as of either (a) the Petition Date, (b) the close of business on the day immediately preceding the Petition Date, (c) December 12, 2011, or (3) such other date as determined by the Bankruptcy Court"
The exclusion of Dime Warrants is a hint - since they're settled for $22MM plus 8.77% and their claim was for about $337MM, it's reasonable to see that a $35MM claim would get in the 1-2% range.
Definition of "Pro Rata Shares" (emphasis mine)
"1.175 Pro Rata Share: [skipping a bunch]... with respect to distributions of Reorganized Common Stock, “Pro Rata Share” shall mean (i) the proportion that an Equity Interest within the Class of Preferred Equity Interest, entitled to receive distributions in accordance with the provisions of Sections 23.1 and 41.6 of the Plan, bears to the sum of all Equity Interests in such Class which are entitled to receive distributions in accordance with the provisions of Sections 23.1 and 41.6 of the Plan or (ii) the proportion that an Equity Interest within the Class of either the Dime Warrants (if determined pursuant to a Final Order to be an Equity Interest or a Claim subordinated to the level of Common Equity Interests pursuant to section 510 of the Bankruptcy Code) or Common Equity Interests, entitled to receive distributions in accordance with the provisions of Sections 24.1, 25.1 and 41.6 of the Plan bears to the sum of all Equity Interests in such classes which are entitled to receive distributions in accordance with the provisions of Sections 24.1, 25.1 and 41.6 of the Plan"
Summing the interests ensures Dime is part of the calculation, too - so their percentage is even more meaningful. (Can't give 9% to a $337MM claim and 10% to a $35MM claim.)
I really should stop reading the board after 1 AM :)