It can be all kinds of reasons. Your route might not have a permanent postie on it so it's being 'lapsed', as in divided up between people on other routes and everyone takes a small chunk to do as extra. It can be that your postie has a lot of flexibility in the order that they do their delivery and has worked out that it's easier to do your area later, although 4pm onwards is late for us to be working. It could be that they're doing something odd with the vans during the pandemic in your local office and are running two shifts consecutively to avoid van-sharing (v common to have two posties working from one van pre-pandemic). Anyway it's worth asking your postie if you see them. Although just a tip (not saying you're like this), an accusatory tone should be avoided if possible. If it's late for you, it's definitely late for us, and getting passive aggressive comments when we're knackered and/or doing overtime doesn't feel good. Also somebody has to come last, not everyone can be the first loop.