V70 III D5 Service intervals – what is mandatory?

Moin together, I’m still new here but actually long Volvo driver, namely since now 19 years. Equally old is our first Volvo, a V70 I TDI. If he is still so good, he rolls soon over the 800k km. Volvo4Life I only confirm there! Now there should be Volvo offspring. There is now a new V70 III D5 MJ2013 R design in the family and, after a long search, with manual transmission. 122k he has been behind him. The good thing has always been to service with Volvo. Nevertheless, a mistake has been made. The service for 90,000km was done two times according to the calculations. Only at 90,000 – OK! Second at 120,000 – not OK? Therefore my question: Are only oils and filters and what is noticeable when looking through? What is the minimum – the common denominator? – because if necessary this “mistake” does not matter. By the way, my Volvo workshop thinks – the only difference is the interior filter and oil filter. Otherwise there would be nothing. Well, I have read in the meantime that For example, the rib belt + tensioner has to be changed at 90,000 (which has happened twice, by the way). What’s the matter? There can be no two opinions about the tasks at the respective intervals, if Volvo does certainly make specifications? LG