But what are we arguing over here? At most 2-3 years. Is that worth it in the long term? The IN will have to live with the 11356s for 30+ years, if you are buying you need to get the best for the time. Already the 11356s feel outdated, this will be even moreso in 2022-4.Have to agree with @randomradio - as mention earlier - hopefully, the sanctioned strength for Frigates will be reached quicker with the addition of these 4 hulls.
It will be very short sighted if the IN thinks the ability to add 4 more hulls of 11356 in the early/mid 2020s offsets it's capability defeicences.
IF there was customisation happening, IF these 11356 were going to have MFSTAR and LRSAM and HUMSA-NG then this would be a very different equation and this deal would be almost too good to turn down but the reality is they are a very very modest upgrade on the existing frigates. They aren't even coming with an integrated mast! Simply calling them "stealth frigates" doesn't mean much.