Endorsed and I also second your opinion. These shopkeepers have an art of convincing and selling. He wouldn't want his reputation go down by suggesting something that would affect his sales. Why would he want a set back in his stock? And I seriously doubt his claim of booking 8 or 10 more sets after people saw your thread.
The "mera to faida aur profit hai agar aap replace kar lain" and "bhaiyyon wala mashawara de raha hoon" and "main khud use karta hoon" are national sentences. If they follow guidelines and regulations they will be out of business and he won't be able to sell them again.
The tyre shop I changed 215/55-16 as it is in same size was giving all sorts of discounts and reasons to get 215/60-16 which as any of you can compare is 3.2% bigger than stock size and that variation is a no go forbidden area. He was also giving me a "bhaiyyon wala mashwara" that aap ki gaari ki clearance buhut zyada aur achi ho jaye gee. Please keep in mind they want to sell their stocks and have nothing to with sincerity for a customer.
Rest bro totally your decision. Just a few members giving you sincere advice.