If I have a OW RTW ticket which starts off like this: KUL / xSIN / NRT (originating KL, transit Singapore, next stop Tokyo) and I want to change it to KUL / oSIN / NRT (stop Singapore), does this require the ticket to be re-priced?

I was under the impression that the rules require me to fly the first coupon (KUL-SIN) as ticketed and then subsequent dates can be changed free of charge; however, I am being told that since the ticket shows SIngapore as a transit, I will have to fly all the way to Tokyo before any date changes can be made. Is this correct?