I think that your pricing on exteriors seem okay, but I have to say that you have been lucky with interiors that can be done well in an hour. I would charge more for the interior jobs as you will sooner or later get the soccer mom van with 2 dogs and 3 kids that will take you 4 hours to do even if you are fast. Increasing the interior pricing and telling the customer that you will charge more if the condition of the car is poor is the way to go. I would charge at least $40+ more for a large vehicle instead of $20 as well because the more you do, the more you will see that vans/suvs are usually in far worse shape than most cars.
As far as the freebies go, I would just keep offering great service and they will keep coming back. Your repeat customers could be charged less each time as it may take less time if it is done more often by you. I would use your rates as a guideline, but warn the customer that each car is different and you have to see it to give an estimate. The only time that I feel that I undercharged is that I told the customer it will be a certain amount and then their car is a mess and it takes longer. I now tell people it will be at about $X, but tell them it may be more depending on condition.
An add-on to consider is engine cleaning. As long as you have a blower to quickly dry the engine, it takes me about 5-10 min to clean most engines and it always gets the biggest reaction from customers. As long as you are carefull and don't spray water where you shouldn't , this would be a great, fast add-on to your repeat customers.
As far as the freebies go, I would just keep offering great service and they will keep coming back. Your repeat customers could be charged less each time as it may take less time if it is done more often by you. I would use your rates as a guideline, but warn the customer that each car is different and you have to see it to give an estimate. The only time that I feel that I undercharged is that I told the customer it will be a certain amount and then their car is a mess and it takes longer. I now tell people it will be at about $X, but tell them it may be more depending on condition.
An add-on to consider is engine cleaning. As long as you have a blower to quickly dry the engine, it takes me about 5-10 min to clean most engines and it always gets the biggest reaction from customers. As long as you are carefull and don't spray water where you shouldn't , this would be a great, fast add-on to your repeat customers.
