Validation and pixel area calculation error

[Sakar771]

1. Whenever I try to validate the LandTrendr map with reference from google earth image, I see the map is 2,3 pixels off from the actual change detected. It's happening almost 7/10 in both loss and gain map.

2. Another problem is, I used,

//For MAG area calculation
var magChange = changeImg.select(['mag']).gte(200).and(changeImg.select(['mag']).lt(800));
var areaPalette = magChange.multiply(areaImage);
var areaPaletteSqM = areaPalette.reduceRegion({
reducer: ee.Reducer.sum(),
geometry: aoi,
scale: 30,
maxPixels: 1e13
}).getNumber('mag');

//For YOD area calculations,
var magChange = changeImg.select(['yod']).gte(1990).and(changeImg.select(['yod']).lt(2020));
var areaPalette = magChange.multiply(areaImage);
var areaPaletteSqM = areaPalette.reduceRegion({
reducer: ee.Reducer.sum(),
geometry: aoi,
scale: 30,
maxPixels: 1e13
}).getNumber('yod');

I used these codes for calculating pixel area in sq.km for both Magnitude and Year of Detection map and found errors.
In 'Loss' map, almost 20% og rmse loss of YOD against MAG map (in pixel area of sq.km)
But in 'gain' map, almost less than 1% rmse loss of YOD against MAG map.