In my continuing quest to kill this batch of wine, I have messed up
the acid balance.

Here is the story:
I have a 5 gallon batch of Cabernet Sauvignon (from concentrate) that
has finished primary.
Prior to inoculating, I measured the reconstituted juice and found
that the titrateable acid was very low, about .3%. I wanted to raise
the acidity to between .6% and .7%.
In order to do this, I used the following formula:

4.1g Tartaric Acid/1 gallon = .1% rise

So in order to raise 5 gallons of wine to .65% (a .35% rise) I
calculated the following:

5(4.1g)/5(1) gallon=.1% rise
3.5(20.5g/5gal)=3.5(.1%) rise
71.75g/5gal=.35% rise

I added this acid to the juice and re-measured the TA. It was up to .
4%
After a 20 min wait, I re-measured and it was still .4%
I added another 20g.

After a 20 min wait, I re-measured and it was still .45%
I added another 20g.

After a 20 min wait, I re-measured and it was still .45%
I then added 40g.

After a 20 min wait, I re-measured and it was still .7%
good

Now, almost 2 months later, I re-measured and the TA is .82
Crap
The taste is very tart. Go figure.

So, what is the best way to add acid? Should I have waited longer
before adding more? Does it take a while for the acid to fully
dissolve?

Where did I go wrong?