You must have really good DIY CO2 generation and/or a very good method of diffusing the CO2. Most aren't able to achieve results that good when combining DIY CO2 with BioWheels. You may want to consider removing the BioWheels sometime down the road.
Since you've got a really good balance and are achieving the levels that you want right now, it may be best not to mess with it. If you were to remove the biowheels now you'd probably end up having to find ways to may your DIY less efficent. Less/smaller CO2 generators etc.
Once you make the switch to Pressurized CO2, it would be a really good idea to remove the BioWheels. At that point it will be much easier to control the amount of CO2 being injected into the tank, so that your aren't injecting too much. This will extend the amount of time that a CO2 refill will last saving you money.