Can I turn more profit on this?

I have a product for a client, very common, where you can register hours your worked by choosing the timespan and the cost will be measured on different parameters like overtime hours, weekend and your salary level.

The product allows you to create different projects and assign employees to them and create special users who are in charge for one or more projects. Each project then has several accounts that you register your hours at, in the end that gives the employer a good idea how the money are spend.

This all runs now at a client is fine. However having just that one client doesn't add much profit and it needs maintenance of course. I'm there for thinking about how I can spin a little more money on that product and maybe you have ideas for me? On obvious idea could be to create a service platform anyone can sign up and use the product for a payment? I don't know how that would satisfy my current client if suddenly others can sign up for it for a less amount.