No. And yes. Directions say 1mL/10g, and that's fine daily. Yes, use a syringe. There's a really long thread about Excel as a treatment for BBA in the Algae forum. Basically, it boils down to long-term use of Excel over the basic recommendation will kill stuff that you don't want killed. And don't ever use the "post-water change" dosage.
Just stick with the directions. Use a small syringe, and do 0.2mL/day.