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.
For my 2 gallon, I measure by drops. 2 drops = .1 mL, the regular dose is .1 mL/gal, so 2 drops per gallon. I got a flip top lid similar to this: http://www.amazon.com/16oz-Plastic-B...irt+top+bottle
and put it on my Excel bottle. Makes it very easy to dose small tanks.
I just looked at the material safety data sheet for flourish excel and it is water soluble. So you could just take the bottle, dilute it 1:10 and now it would be 1 mL per 1 gallon dosing, making it easier to dose for the 2 gallon spec.