When astronomers "look into the past" are they accounting for the expansion of space? Every time astronomers look "13 billion" years into the past, not only is there more space than there normally would be at that instant which increases from observation to observation, but there was also expanding space for eons prior to that which must offset photons over those billions of years. 

I haven't seen astronomers ever actually state they've reconciled that difference whenever they talk about their observations, so 

1: Do they actually?

2: How do they?

3: How does that change the reality of their public statements?
When astronomers say something is seen "13 billion years in the past", this is (in most cases) a model-dependent statement, but a perfectly valid statement that tells us how long the light from an object has been travelling to us and which does take account of universal expansion.

What has actually been measured is a redshift, and to convert that into a "look-back" time requires an understanding (and a model) of the expansion history of the universe.

In the actual scientific research publication, as opposed to a press release, the details of what assumptions have been made will be stated. The current uncertainties in the cosmological parameters are small - they would not for example lead to uncertainties in the look-back time of even a few percent.

However, there is always a possibility that our understanding of cosmological expansion is wrong. In particular, the assumption that the cosmological constant is constant might be wrong, in which case there will be systematic shifts in estimated look-back times.