Only if it still pays! Don't try this without researching your customer base.
This fascinating article on customer service offers research on how much service may or may not have a return on investment. It seems there is a 'delight point' that just might not be worth the extra money to provide, but it does depend on the type of business.
"Consider service levels, specifically average time-to-answer, which is one of the most common metrics used in call centers. Service levels—often based on regulation or historical precedent—are set by call-center managers and then used to calculate staffing requirements. But service levels are challenging to maintain and costly to improve: raising them by 10 percent requires much more than a 10 percent increase in staff."
Much of this study is based on wait times, such as in call centers. Take the link to read more. Perhaps not all customer service is critical to business. Certainly there's a fine line. How long should YOUR customers wait? Are you willing to add staff to improve service, or do you think it's so close the added staff/$$$ won't make a difference?