Leave your prices alone for the moment.
Make the change over to wfp ASAP, get used to it, while you're at it clients will be saying stuff like, "I suppose the price will go up now!" And you can reply, "No, there's no difference in price! What would be the point, mind you, I will have to put prices up in the new year anyway. I haven't had a price increase in 5 years!"
Keep saying it, they'll get used to it.
Don't worry about prices yet, think about it, you've been able to afford to spend out all the extra to buy wfp on what you are charging, and you're still alive! Soon it will be helping you make your living more safely.