The current way the average response time for sellers is calculated/shown is not all that fair to all countries (eg. those in a very different timezone to where the majority of buyers are) and not all that informative to potential buyers since the avg. response time shown (eg. to buyers) takes no account of the time of day/timezone.
A problem with it as it is is that a seller in a country in a timezone very different to that where the country/countries with the most buyers are could end up with quite a high response time if it’s sent out of the seller’s normal working hours (eg. 1 or 3 AM their time). Especially if multiple messages are sent around then and few from potential buyers in their own timezone recently. A high response time could then lead to fewer orders/messages sent to that seller, including from people from their own country/close timezone (eg. the average response time shown could be a lot higher than the actual response time if that potential buyer seeing it sent a message).
What might make the response time fairer for sellers is to make any messages outside normal hours for the seller (eg. Normal office hours) be excluded from the response time calculation (like someone thought it used to be), as well as to show that to the buyer somewhere.
Store Multiple Average Response Times for each Seller option
Another option would be to store multiple average response times – ones for different times during the day. eg. Split the 24 hour day into about 4 periods (so 4 six hour periods), and store an average response time for each of the 6 hour periods, eg. 00:00 to 06:00 for 1st average, 06:00:01 to 12:00 for second avg etc. There could be more periods (averages) stored if more accuracy was required. It could still be based on the last 60 days (or it could be changed to eg. 90 days if there were not enough messages in each of the 6 hour periods).
Doing it the above way could show a more accurate average (or expected) response time to the potential buyer based on the current time at the seller’s location. If there are times with a quicker average response time than the current one, maybe it could indicate that to the buyer on the seller’s profile or when you hover over the response time/click on it or click to send a message.