Dear Laura,
I'm not sure I will give you the best way or not but from my experience, the number is out of order because of you have delete a certain representation rule and create the new one. Yes I understand that is not a big mistake but you just want to have a proper list of number. So my humble suggestions here are:
1. Reconvert the symbology to representation again. And load the rule back follow the right order.
2. To load the rule, first make sure you save the representation rule by click at 'Save Rule'. This action will save the rule to ESRI default style.
3. Lastly, dont forget to delete the first representation that you have convert at ArcCatalog. Right click on feature class>Go to Representation tab>Delete the oldest Representation.
4. Enjoy!
p/s: You also can apply the representation automatically if you are using VST.