Mastac, welcome!
in this case the pool tech's readings pretty much matched your own, and it sounds like they brought you back from your acidic TA crash. So no harm done there. Now its time for you to retest using your kit and to post your results
However, for the record, many pool techs are not well informed about the research that underpins TFP...their vendors -- the pool chem mfgs, likely prefer to keep it that way
Weekly service meants they CANT use the TFP method so they really only know about using stabilized products and dumping water when things go wrong. We have a number of pool techs who actually come to TFP to learn more of the science behind it. But they have to manage the pools they serve a bit differently than the simple, daily ways of TFP.
So the best course for someone new to pools is to stay in control through knowledge and by never adding anything to your pool for which you don't understand the consequences.
As you've likely read, pucks and powdered shock adds either CYA or CH constantly, and the fact is that if CYA is a moving target you can easily find yourself dosing below the required "kill zone" for effective sanitation -- the chlorine:cya relationship is the single most important scientific underpinning of TFP
That is why you have more control using liquid chlorine, it is not stabilized" - nothing else in it -- whether its grocery store bleach or 12.5% "pool chlorine" you purchase at a pool store. The only difference is the percentage of strenghth for which you use to pool calculator here to determine your dose.
If you do use supermarket bleach, the only thing you have to worry about is making sure you don't buy these new "splashless" or scented" kinds, which will cause foaming. I personally use chlorine that I buy in refillable jugs from my pool builder/techs because I don't have to carry as much (as its stronger) and I don't like generating so much waste with empty bottles...our recycle service only comes every two weeks
But when I recovered my "foreclosure swamp" I used cheap bleach from aldi's and it worked just fine...in fact, it worked in a way my pool tech couldn't...after $700 worth of attempts. I can tell you that the pool tech in question, who still closes for me (winter cover is heavy) and services mechanical for us, says I have the best water in town and is now a believer
But when people pay him to service their pool weekly and are unwilling to test or dose themselves, then he has no choice but to use the products available to him and fight the ongoing problems they cause.
You see how that works?
I hope this helps you feel comfortable using this resource to manage your pool. Others, like the tech, and even some pool store folks, may mean well, but they can't guide you on a process they don't or can't use, so sometimes the advice conflicts.
Eg "Your pool is green. Put this cal hypo in. You're selling the house? Use a LOT of cal hypo? Still green? Here's some more cal hypo...."
End result? You were sold a pool that might be, if not 1400, still well above your target parameters for calcium
So retest and let us know your results.
Cheers to a trouble free pool!