How did you measure .25? Using the standard Taylor FAS-DPD test you can only measure .5 (when you use 10 ml of water) or .2 (when you use 25ml of water). Do you have the Taylor FAS-DPD test? Drop tests are titration tests--you go till the color changes and it's either one value or the next. For example, your FC level cannot be .25 with the Taylor test. It can be 0, .2 or .5, or any multiple of .2 or .5 (.4, .6, 1, 1.2, 1.5, etc.)

How are you conducting your own FC/CC test? This concerns me.
Are you adding DPD powder until it turns red, then counting drops from the brown bottle, 1 drop being either .5 or .2ppm until it goes completely clear? ( set it on the white label to make sure I've gotten out the last tinge of pink)

Are you then, adding to that same solution 5 drops from Reagent 0003?
Is it turning pink or red again?
How many drops does it take to make it go clear?

I've not tried the 30 minute drill--it's new to me, but I'm trying very hard to get you over the hump of fighting the contaminant and back to maintaining a normal pool--and your regimen should have made it clear by now....so either something else is going on in your water or I'm not communicating correctly or completely with you.