Your income is in the range that you are normally entitled to the Working Income Tax Benefit. However if you are a student for at least 13 weeks full time, you are not eligible. Whether you need to use the tuition credits in 2016, you are required to enter the credits, and whether you enter the credits or not you are not entitled to the Working Income Tax Benefit. That would be the difference of $1000 on your tax return.
http://www.cra-arc.gc.ca/bnfts/wtb/fq_qlfyng-eng.html#q2
