(S)-methoprene

[Coffeenuts]

I have one cat and one dog and I need to purchase more Frontline Plus for both of them.  I am considering buying it by the vial to save a few bucks.  Some vial resellers suggest that the Frontline Plus product works for both cats and dogs providing the right dosage is used.  I have the original packaging for the last supply of Frontline for both animals which had the single dose applicators.  The active ingredients listed on the front of the packaging on both boxes provide different amounts for the (S)-methoprene ingredient; 11.8% for cats and 8.8% for dogs from 23-44 lbs.  Is this difference significant enough that I should be concerned about buying one product for use on two different animals?

[Coffeenuts]

Please speak to the difference in (S)-methoprene ingredients in more detail, thanks.

[Aleda M Cheng, D.V.M., C.V.A]

Please just buy the individual packages.  It is too easy to overdose using multiple dose vials.