Incoterms 2020, Incoterms 2010, and Incoterms 2000 recognise this and do not prohibit alterations/variations of the rules.  Wording to this effect can be found in the Introduction section of Incoterms 2020, which is a replica of Incoterms 2010 except for the phrase: “… to vary the point at which delivery is made and risk transfers to the buyer” which in 2010 was “… to vary the point at which the risk passes from the seller to the buyer”.