Increment denied on MACP after pay protection under FR 15(a)

I was joining in GP2400 in Chennai in 06.08.2012 and promoted in GP4200 in 04.05.2017. Thereafter Igot transfer to Chandigarh on 17.07.2017 in my own request and joined in Chandigarh in GP2400 after pay protection. As per para 23 of DoPTs OM 22.10.2019, I got MACP in GP2800 on 07.08.2022 (after 10 years) after including my past service and after ignoring my past promotion. On MACP, I requested to fix my pay on DNI i.e. 01.01.2023 and my pay was fixed after granting one annual and one promotional increment as ler CCS Revised Pay Rules, 2016. Then i got promotion in GP4200 on 01.01.2023 and i got only difference of pay in pay level as i got promotion in the same level which i got earlier in my old organisation. Now, the ZAO denied my promotional increment on MACP stating that i have already got the oay protection benefit on transfer and i will got increment only when i will surpass the GP4200. I have given lot of reply but he stating the Railway Boards letter dated 28.01.2020 which is only saying about the pay fixation under FR-15(a) and subsequent promotion in the higher or same level, but there were never mentioned about the pay fixation on subsequent MACP. So, you are requested to please clarify my doubts that whether i am eligible for promotional increment on MACP as the MACP and PROMOTION are both the different in nature. MACP is clearly on counting the total service but ZAO made observations and simply denied the increment. Please do the needful and provide High Court or CAT order on my issue.