How can calculate isotacticity(I.I, mmmm%) of Polybutene-1(PB-1)?

Hello, everyone

I am in charge of NMR operation. I would like to calculate istactic index of PB-1 samples which are batch-sample and commercial sample. In some patent, they calculated I.I by using integration area of 28ppm ~27.6ppm(27.73 ppm, mmmm) and 5 times integration area of

As I know generally, I.I is calculated by using ratio of mmmm part and other part(mmmr, rmmr,mrrm,....).

What is the difference between both methods.

Please help me.

Thank you.