Does my combined rating evaluation 80% or 90% after VA grant for my insomnia?

Hi, I have a question about my combined rating evaluation. I filed disabilities compensation for my insomnia secondary to my tinnitus and my OSA/Obstructive Sleep Apnea secondary to my insomnia on July 31, 2020. VA approved my insomnia 50% assigned from July 31, 2020 but denied my OSA, so my rating disabilities is up from 70% to 80%, and the rating decision indicated: 

            20%  from  Jan 22, 1975                  30%  from   Apr 23, 1979                  60%   from   May 31, 2007                  70%   from   Sep 21, 2019                  80%   from   Jul 31, 2020

(got my left knee disability 20% in 1975, got my in tinnitus 10% in 1979, got my diabetes mellitus 20% in 2007, got my cataracts 30% as diabetic complication from 2007, got my voiding dysfunction 20% as related to my diabetes mellitus in 2019 and got insomnia 50% as secondary to my tinnitus in 2020)

The way I understand, VA should grant me the rating percentage from 70% to 90% instead of 80% because my insomnia was granted 50% on July 31, 2020. In the box of 70% on the Combined Rating Table, if I was granted 50% more; my combined rating would be 85%, therefore it must convert to be 90% as VA website for combing example: 

Examples of Combining Two Disabilities

If a Veteran has a 50 percent disability and a 30 percent disability, the combined value will be found to be 65 percent, but the 65 percent must be converted to 70 percent to represent the final degree of disability.

My question is I should receive the combined rating evaluation of 90% not 80%, correct?

Thank you.