When I purchased my 2017 X1 in December 2016, I also purchased the BMW Ultimate Care + 1. When I hit 20K miles, I had the oil changed and wanted the wipers changed. I was informed by the service rep that it is too soon to replace. Therefore needing wipers I went to Costco and purchased a set for $15.00 vs the $70.00 from the dealer. Today, 6 February 19, I went in for the 36K maintenance and asked them to replace the wipers under the maintenance agreement. Well now I found out that I voided the agreement because I put the Costco / Goodyear wipers on. I asked could you not replace in order to provide good customer service. The service rep said no because they have to return the wipers to BMW. Is this true or is the dealership representative giving me some BS?