Couple of things:
1) 1 gallon of 8.25% bleach SHOULD add about 12ppm of FC to your pool
2) When you measure your FC and CC, use the 10ml line and not the 25ml line. You'll use up your reagents too fast and the .5 measure for each drop is more than accurate enough.
3) When measuring CYA do it the same way every time. I hold it at waist level and face into the sun. Then I spill the solution back into the squeeze bottle and do it again, at least once, sometimes twice, using the same solution until I'm satisfied I've gotten a good reading. The scale on the side is a log scale so halfway between 30 and 40 is NOT 35, it's less. Your guessing at "38" but it may be lower if it's not right on the "40" line.
4) If your FC is 3 and you add a gallon of 8.25% bleach to your pool you'll be (nominally) at 15.
5) You need to check and adjust your FC level at least 2x/day, preferably 3x until what you are fighting is dead. You CAN go a bit higher but may bleach the pool a bit.