BobVila.com

More concrete

The concept is OK and in fact has a lot going for it.

Post set directly into concrete are prone to rot (even treated ones) as the post will strink and form a gap which will trap water.

One problem with doing it the way that you trying to do it is that there is limited overturning resistance.

But it would be ok for relatively low decks (probably no more than 3ft).

Now Fairfax Co shows 3 different details. One using an underground bracket, one an above ground bracket, and one with the post set in concrete UNDERGROUND.

http://www.fairfaxcounty.gov/dpwes/publications/decks/

I think that the last one is a very, very poor design.

Note - that they say to use a heavly hot dipped galvanized or stainless steel for the bracket.

And if you have the end of a post underground I would treat it with a water replent, protectant (Jasco has several) before installing it. The end grain is what will wick in the moisture and this will help stop it.

Now as to your question.

If the unevenness between the end of the post and the concrete footer is no more than 1/2", 1/4" is better, then it will be OK.

The other think is to Strap the post together that will keep them inline and plumb in one axis. Then a couple of diagonals to the ground to keep them plumb in the other axis.

Then backfill and COMPACT around the post. Use crushed gravel in the 1/2 - 3/4" range. And compact it every few inches. And compact it some more.

Some soils will work for this, but others are either too sandy or have too much clay and will hold moisture. The advantage of the stone is that lock together and is free draining.

Now if you hole are already holding water for days at a time you don't want the post in the ground at all.

Done right that will lock in the post.

You should be able to remove the supports, but it might be easier to just start builting the deck and later removing the supports after you have enough of the deck built that it locks the top of the post into place.

post bracket