The OEM engine oil was fully synthetic the service person was telling wrong info. Btw the owner not changing oil regularly then what is the point of doing it in better way as explained. Same or better way the service center - FAAS doing the regular service. Also 5w -40 is wrong engine oil is putting to the car .Ford recommends 0w -30 fully synthetic for bs6.
Thank you for sharing your knowledge, But ecosport is not a BS 6 engine. If you are working with BS 6 Then definitely go with 0W20, 0W16, and 0W30 as per oem brand recommended.