I'll bet that there are plenty of astrophysysicists who are mathematicians who could calculate a very different distance by calculating a gradual change in math and physics into it. But why do this when it is so much easier to use all kinds of constants that we don't for-a-fact know existed more than a million years ago?
I'll concede that scientific understanding of the distant past is a projection, and that the universe changes over time. You're not talking differences of degree though, about whether the universe is 10 or 15 billion years old - you're saying (in the religion thread) a few thousand or (here) a million, which is simply not true. That can and has been easily tested right here on Earth. Isotope analysis such as radio-carbon dating has proven far beyond reasonable doubt that the Earth is over 4 billion years old.
If a person said, "It looks like the universe is 13.5 billion years old according to this evidence or that," he would be okay. But since our pottery only goes back about 5,000 years, and since radioactive dating has its anomalies and flaws, we don't know even close to for sure. All our evidence for the universe age of 13.5 billion could be evidence that has been affected by any number of things that could be causing false readings in the way we interpret them.
On the other hand, if God created the universe about 7,500 years ago, and placed into the creation all kinds of things that could be interpreted scientifically to show that the universe might be older, how would we know?
There is absolutely no proof that the universe is much older than 5,000 years... about how old we can date the oldest pottery and "statues." So, be honest, and say it the way it is... not the way you would like it to be.
We don't know that the earth didn't have a population in the past, that was twice the size of today. And that most of them were destroyed in some apocalypse. The Bible shows that this is possible in Noah's Flood, and Sumerian writings in the Epic of Gilgamesh more or less agree that it could have been that way.