I was logging my timing today and my idle ignition timing is around 25 to 30 degrees advanced. Then during acceleration the timing drops.

 

What year and what engine?

22-25deg BTDC would be about right, 4cyl may be a little more

Yes, when accelerating engine gets a Richer air/fuel mix so it burns faster and spark timing drops under 20deg BTDC

Spark timing 101, just the basics
A normal 14.7/1 air/fuel mix takes XXXX amount of time from when its ignited(spark happens) to when it reaches FULL explosive power
You want FULL explosive power to occur when Piston is at 10deg After TDC, so it has good leverage to push down on the crank to add to its power

So spark happens Before TDC to account for the XXXX time it takes the piston to move to After TDC when you want FULL combustion to happen
RPM, well the burn time of XXXX doesn't change but the speed of the piston does, as it moves from 10deg BTDC to 10deg ATDC faster as RPMs go up
Thats what the springs and weights in a distributor were for, they would change spark time to more advanced, 25+deg BTDC, as RPMs went up, all the way to 36deg BTDC

Then there is Load advance, as said, a richer air/fuel mix burns much faster, XXX, so spark needs to occur closer to TDC, less advance when a richer mix is added
Thats what Vacuum advance did on older distributors, it would lessen the RPM advance to compensate for the short burn time

With computer control the RPM advance is easy, its just tach signal, the load advance is a bit harder but way more accurate than vacuum advance was
Thats what the throttle sensor, and MAP or MAF sensor was for, calculate engine Load

At idle an engine has basically 0 load, so a 22-25deg BTDC is fine, it actually better for emissions, a more complete burn but less power

As said RPM advance can go up to 36deg BTDC
But engine load and richer mix will lower that to get FULL explosive combustion to occur After TDC, but not too far after or you won't get full power of that explosion

 

It's a 2000 2.5. What has me scratching my head is other cars I've watched the timing on typically show 8 to 10 degrees at idle and when on the throttle/under load go up to 47 degrees instead of dropping.

 

Base spark timing with no Vacuum advance or Load advance would be 8-12deg BTDC, and you always set base spark timing without Load advance
With the advent of distributorless systems there was no need to set base spark timing as the crank sensor and its tone wheel were fixed, so base timing was set, the computer or spark module would do the rest

As emission standards got stricter engines needed to have a more complete burn, lower emissions, and lower emissions at idle was the big deal
This is where "auto stop/start" comes from on newer vehicles, while yes it does save fuel it also means 0 emissions when engine is off, so car makers can meet stricter emissions each year, and why on some models you can't disable "auto stop/start"
So in 2000 the emissions standards at idle will dictate your spark timing, it has to be advanced enough to get a complete burn but not too advanced so engine starts to over heat
The issue at idle is overheating, so mix can't be too lean, which causes overheating and pre-ignition, so it needs to be richer but not too rich as that causes higher emissions

EGR(exhaust gas re-circulation) was added to lower emissions under acceleration
When you run a richer mix it burns faster/hotter which raises the temp inside the cylinder, which is why engines can ping/knock(pre-ignition) but only when when accelerating, the air/fuel mix self ignites because cylinder temp is hotter
And this higher cylinder temp creates a spike in NOx, a toxic gas that comes out the exhaust that CATS can't clean up
By adding hot exhaust gases to the intake it causes the richer mix to burn a little slower and not as hot, so lowers NOx emissions, and lowers possible ping/knock issue

With this slower burn time for richer mix the spark timing can be more aggressive, more advance, to get the FULL explosive power closer to 10deg ATDC for best power added
Some engine tunes shoot for 5-8deg After TDC for even more power added, but it gets dangerous when you get closer to TDC, as you can break pistons and bend connecting rods, lol

You need to work you way backwards from 10deg After TDC
You can look up burn time for different air/fuel mixes, and crank/piston speed from 10deg BTDC to 10deg ATDC by RPM
It is its own science and there is alot of math
This is just basic info

 

When I ran the original scan I was using the Torque Pro app. Using ForScan the numbers are what I was expecting. Timing at idle was around 7.5 degrees and part throttle timing was 20 to 30, instead of 30 degrees at idle and timing dropping as the engine speed accelerated. I appreciate all of the information you provided Ron D.