I wish i kept detailed maintenance records back when I first got my V6! I'm almost exclusively DIY'ing. I totaled up some estimates previously and it was around $2,300, most likely up to around $2,800 now for 47,000 miles and 5 years ownership now. Did you forgot to record some of the oil changes? I see a 33,000 mile gap at one point. The only oil to use for that kind of distance would be Amsoil signature series with an additional finer oil filter installed.
TO AVOID A VERY LARGE POTENTIAL EXPENSE, HAVE A SHOP CHECK THE TIGHTNESS OF THE SPARK PLUGS PERIODICALLY! These V6 engines like to work the spark plugs loose over time, and when they are loose enough the force of combustion can tear the threads out of the cylinder head. When I got my car at 135K miles, one of my spark plugs was not even hand tight! I try to check mine every 15,000 miles to be safe. if the shop wants labor, don't pay more than $50.
Shops like Discount Tire will do free rotations and balancing if you buy tires from them, even if you don't in some cases. Try to time the rotations so that the tires wear evenly and can all be replaced at once. Check for tire rebates when buying, usually they will require 4 tires for the rebate to take effect.
Cabin air filters can be replaced in under a minute, and without any tools.
Replacing the air filter in the V6 is kind of a pain, and requires tools, so i could understand not wanting to do that. Don't pay more than $20 labor.
Things like oil changes with rotation should be in the $50-$80 range. They should do the inspection for free, they are looking for their own work to do.
Tires will vary widely depending how cheap or expensive you go, but for the small and common 205/60/16 it shouldn't be more than $550 for 4. Check out the Discount Tire website for pricing, they are pretty competitive, but even then there is huge profit in tires. If you haggle, you can get them to drop the price.
Don't pay more than $80 for an alignment. Also don't let them upsell you for adjusting camber. Adjusting camber in these cars requires different parts, so it is just toe they will be adjusting.
Timing belt and water pump + tensioner and pulleys should not be more than $800. The second one was way too early.
Brake pads with rotors shouldn't be more than $250 per pair.
Also, if you really want to track total costs, track fuel and insurance costs as well!
Example: