@rohiitian , both the applications 1x18 lots and 3x6 lots would enter into lottery and would have more or less same probability of allotment if the issue is oversubscribed 35-40x. It's upto you now if you want to try luck of one person vs luck of 3. If I was in your place I would go with single application of 18 lots.
Btw, as Sharp Chucks if a fixed price IPO. Some portion of shares from NII's will be transferred to retail quota based on the extra retail subscription. So, overall NII oversubscription will be 50x and not 36x. So, for 18 lot application chance of allotment will be roughly 36% and not 50%.