Texas and it’s whopping 155 delegates was primary date was ordered changed by the two federal judges from a March Super Tuesday state to an April 3 primary date. Texas was also changed from a winner take all state to proportional representation. These two changes have dramatically lowered Texas’ influence on who the nominee will be. My understanding is the change from winner-take-all to proportional-representation was a result certain rules changes made by the Republican National Committee. What were these rule changes and how did they come about?
The rule change you're asking about is probably the one that specifies all GOP primaries prior to April 1 would distribute delegates proportionally, rather than wiiner-take-all.
It was designed to a.) extend the decision over a longer period of time and involve more states and b.) insure that a John McCain didn't happen again (McCain never won a majority of primary voters in any state until his home state, Arizona, put him over the top on the delegate count).
Even though it's now scheduled for April 6, Texas probably remains proportional because it was originally scheduled in March.