New funds come up with NAV of ₹10, but well-established funds with good historical performance and similar categories or types have NAV in 3 figures.
The returns are on the amount you deploy in the market. Not at what price of the NAV you invested in.
As an example, nav of ₹10 becoming ₹12 is the same as ₹100 becoming ₹120. So there is no difference for a fund for a NAV going from ₹10 to ₹12 and ₹100 to ₹120. Of course, in shares, one can still argue (it is still an argument) that small-cap companies can make more significant percentage moves than well established and large companies, but that isn’t true for mutual funds.
NAV is a price assigned to its units, and ₹10 per unit is merely a number to start the process. One should never invest in an NFO unless the new fund offers some unique investment perspective, but it is pretty rare these days.