Frontline Plus has different dosages and I just recently ordered the one for dogs weighing 23 – 44 lbs. I was worried that she would not get enough protection from the 11 – 22 lb dosage. She is a cocker spaniel if that makes any difference. Maybe I could use it but not administer the whole vial? I was confused a bit because other flea control meds have different weight charts/dosages. Thanks for your help!