We have to grade prospects in Pardot, but we noticed that the rules we are writing work only on the first assignment. For example, if a prospect is graded for the first time and gets a grade of A-, changing one of his fields it should get a grade of D. Instead, the prospect has been graded as C-. Any clue on why this happens? The first time we grade a prospect it adds a letter (or a part of a letter) beginning from D. From what grade does it start the following times? Is there a way to begin again from D or to reset the grade? One thing more: what is the order the actions in an automation rule run?
Grading in Pardot is based on profiles and happens when a prospect matches or does not match profile criteria, in which case the grade increases or decreases by the amount specified in the profile. So a prospect has to be assigned a profile in the first place in order for grading to work.
You can match criteria manually in the profile tab of a prospect’s record (see screenshot). Here you can also reset matches. To 'reset' a grade you have to reset all the matches. Matching can also be automated with automation rules.
Grades run from F (poor) to A+. Grading best practice is to start at D, which is the value that is assigned on conversion.
So the behaviour that you describe is set up in the profile, in which the criteria and the adjustments are defined. to change this, create a profile and define the desired criteria and adjustments. After that, manually match criteria or set up automation rules to do the work.
With regard to order of execution of automation rules: Generally you can't rely on such order. Check out this post in salesforce success community.