Scangauge X-gauge 'GAS' correlation with fuel gauge

My attempt to understand the fuel gauge of the prius.


From this thread -(thanks) I programmed my scangauge for the gas gauge sender.
http://priuschat.com/forums/gen-ii-...77-updated-list-gen-ii-xgauges-scangauge.html
Gas Gauge 05AC 010582A40000 1808 006400040000 gas xx.x % full

This reading varies a lot, especially at lower fuel levels. Acceleration and deceleration will show cause significant changes in the reading. The update is around 65 seconds (by my count while driving). Whatever the car is doing at that time, will be the readout for the next minute. The car has built in slope sensor detectors for the gas level reading , but I believe that the cars accelerating / decelerating throws off the fuel gauge and limits my driving range. I'm constantly changing speed when I deliver the mail, so this effects me more than the average driver.

At the lower range , it showed at 7.5 when the 'low fuel alarm' lit, then read 30.0 when I started the car back up after stopping minutes later , and was on a slight slope. Twice I've noticed the readout to be 7.5 at the low fuel light, once at 12.0. I was driving, and may have missed the true reading.

My question has anyone checked how accurate this reading is in warning the car will run out of gas. I'm not one to try running dry, but have read others have to test the dash fuel gauge, and would expect watching the readings of the fuel sender would be much more accurate.

If this has already been posted, please refer, I already did a search.
I drive a lot, fill up around every other day, so this does effect my daily life, if you like to fill up at 3 bars, go right ahead. I did believe I have a smaller fuel tank/bladder, but am considering possibly the fuel gauge reads low prematurely. I usually fill up after the low fuel warning, driving up to 50 more miles, with around 8 gallons. Additional data for GAS at low fuel notice : 12.5,7.5,7.5.

Lowest data number read 2.5 .