Itr1 or itr2 if exempt income us10 is more than rs. 5000

Hello experts,

I am a salaried employee and have filed ITR2 last year, because I was told that ITR1 can not be filed if exempt income under section 10 is more than Rs. 5000. Since Conveyance allowance (Rs. 800 * 12 = Rs. 9600) comes under section 10 and is obviously more than Rs. 5000, I was convinced to file ITR2. 

However, it seems lot of other people, including my colleagues who also have their exempt income more than Rs. 5000 actually filed ITR1 and it was also accepted by IT department. Hence am confused which form to fill up this year - ITR1 or ITR2?

Since ITR1 is simpler, is it ok if I file it this year or is it necessary to stick to ITR2 once you've filed it up?

Moreover, efiling website gives only 2 options - ITR1 & ITR4s, so could someone please help me decide on ITR1 or ITR2?

Thanks and regards,
-Vaibhav