Chance of success MSA not working properly

Hello all,

We have the chance of success field based off of the stage that the opportunity is in. Based off of the chance of success we can calculate a value, so it is very important that this field (chance of success) is updated as soon as the stage changes. Currently on the MOBILE DEVICE MSA the sales stage defaults on the first stage, which should have a 10% chances of success but is 0% until it changes to another stage. Is there a way to make the stage field not default to a stage, so the user has to choose a stage?

Thanks,

Brandon