MPSCS Towed Number
The Pro-96 displays them in Hex kind of. You need to look at the first number 4 which is tower district 4, nothing to do woth MSP district. Then you can convert the remaing two numbers to decimal and you will match up with Radio Reference.
I am not sure why the Pro-96 uses hex but it is really easy to convert. The reason I chose hex for my web lage was to make it easy for GRE radio ownwers to look up and or report tower numbers.