Personally, I would not expect that Carenado to be accurate. They make realistic looking aircraft, but that is about it. If you just want to get where you are going faster, fly the Carenado. Just don’t buy an Arrow III IRL .
Regarding the tables, what you first do is figure out the power setting you want to use; i.e. Economy Cruise 55% power 2500 RPM. At 4,000’ MSL, you should run 21.3" of manifold pressure at 2500 RPM. Then find the matching TAS table, draw a line from 4,000’ on the y-axis until you intersect the right temperature on the slant lines, then go straight down to get the book TAS. All of this assumes you have leaned the mixture as required by the chart (which in this example would be peak EGT). There are examples on the charts (see the text box and the corresponding dashed line) that aren’t too hard to follow.