Though you pay off the entire credit card bill, maxing out your credit limit every month will have a negative impact on your credit score. Credit utilisation ratio has a considerable weightage in calculation of your credit score and exceeding above 50% of the credit limit could have a negative impact on your score despite your on-time payment. 

If your spending is so much, you can request the lender for increase in the credit limit. This could help you keep a low utilisation ratio and improve your score as well.