You need to read the example slowly and carefully, they way a moron reads a picture book.
The only disparity in the two houses is the actual FMV of the houses, which is the base of the real property tax. A 25/1000 tax levy on a house with a FMV of 100k results in a 2500 tax. a 25/1000 tax levy on a house with a FMV of 200K results in a tax levy of 5000, that is, for the math challenged like you, twice the amount of tax without receiving twice the amount of government.
There is no legal disparity between the two assessments - they are both assessed at their respective FMV.