Arranging by Math?

[Matthew]

I'm reading the Glenn Miller biography by George T. Simon, and I come across this interesting paragraph that has the comments of Bill Finegan:

Finegan found that Miller's organized, corporate-executive approach also pervaded music itself: "He like to work out things mathematically, especially his harmonic sequences. I'd figure out my own without using math, and then he couldn't wait to get to a piano to see how my sequences worked out mathematically. He always kept touting the Schillinger method of arranging, which used the mathematical approach, and I always kept rejecting it. I felt math shound not be the instigator of music. But this organized method suited him perfectly. It was a practical rather than an idealistic approach to music, which is exactly what his band was all about, too."

Is the "Schillinger mathematical approach" still used in arranging? If so, who uses that method? It's not an earthshaking matter, but interesting none-the-less.