Here's what customs rules in India state (the 'free allowance' referred to is for personal items, and the duty-free allowance of alcohol cigarettes):
One laptop computer (notebook computer) over and above the said free
allowances mentioned above is also allowed duty free if imported by
any passenger of the age of 18 years and above.
So obviously, your friend who was carrying two laptops (one work, one personal) was stopped. Technically, the customs officials were correct in trying to charge him duty on the second. Note that specifically for Indian citizens returning from work abroad are allowed to bring back 'items of professional use' but computers do not count as 'professional use' items as they can be repurposed by anyone.
Apart from that, passengers above 10 years old flying in from most countries are given a duty-free allowance of items worth INR 35,000 as long as they don't fall into one of the restricted items list such as alcohol / cigarettes.
The ambiguity lies in whether a tablet would be considered a 'laptop computer' or not because it's not defined within Indian customs law. You do have the INR 35,000 limit (which your iPad may or may not fall within) which you could claim this under, but that won't leave headroom for your watches.
It all boils down to what customs official inspects your baggage. I have been waved through most times without my baggage getting inspected (at any airport - India or outside, so I should count myself lucky!). Chances are if you look like a working professional, you will be stopped for inspection. They might be less likely to stop someone like me, because I usually wear my university logo clothes when travelling.
Also, if you're carrying seven watches, chances are customs officials will think you're carrying them for the purpose of reselling, and thus more likelier to make you pay duty on those items. Again, this is anecdotal evidence from what I've seen on how customs officials behave in Indian airports.