Is your 10% being given for unforeseen circumstances? Setting up evaluations of cost comes with experience as a valued practice I find an average of moderation found in fact. We have many different models found in pricing for goods and services. Many have no basis of fact to the evaluation. There is the one time only model. Then there is a long term model. I work with the, I do not know the duration of use, of product or services model. You may need more than one model to form a customizing model to your customer base as this can be a sure win for you. The basics stay the same. Value the customer or client the interaction must go both ways.

“Open Mind” 360: 2030

“Open Source” & “Local Support”