stabilizing question

Need help with stabilizing I had 5 gallons of cider racked in a secondary over 2 1/2 lbs of rasberries I reracked last night off the rasberries and added 1 tbs sorbate and 1/2 tsp metasulphite i topped of with 1/2 gallon of store bought cider that contained some metasulphite already could this create an issue with possible too much of it between the 1/2 teasp i added and the amount in the 1/2 gallon i topped off with?

I thought sorbate was much more common than sulfites in store bought juice, but either way, I don't think it matters.