This is an approach you can use that will help reduce any confusion
Pull out the list you are working with
Check in the plan item add / modify section if the plan you need exists - if it does not then add the plan in. If you see a plan that you could use but needs a minor modification in the name then do it now.
Now search all the plan items category wise and
Inactivate the plans you do not want ; Set the plan as weight / species specific if needed ; set the price, volume discount and weight surcharge for the plan if applicable ; now set the reminder, flag to show in past services and substance logs
Create Groups for plans that point to common stock
Add "Stock without PO" in hand that you need to reflect manufacturer name , lot id and expiry date
Create Wellness Packs and Packaged Plan Groups
If you wish to implement the Purchase order process of ordering stock then you need to link the plan to the inventory / vendor items (after you have added the vendor items of your distributer)