Revelation is consistent in its use of numbers.  If they fail to be consistent to our interpretation is because we fail to grasp the full meaning.  The numbers which have peculiar meanings are these:

One:  This is the number of God  Deut. 6:4 Bible

Three:  The Trinity. The triangle is the smallest unit in geometry.  In the Trinity its reveal as the Father, the Son and the Holy Spirit.   

Four:  Is the world number, four directions, north, south, east and west.  The four winds, and the four seasons.  Four empires of Daniel, four Gospels record the life of Christ.  These number is used by God when dealing with earth and man.  But is also used by God in heavenly presentations:  The cherubim of Ezekiel, the four living ones, four horsemen .

Six:  The number of evil, Satan's number 666 (Daniel 3:1 REV. 13:18 Bible

Seven:   The number of completeness, but not of perfection.  The dragon has seven heads, indicating his complete reign over the whole earth.  The seven reign is the world seven empires.  Number seven shows the subject in completeness, the seven churches, seven spirits, the Holy Spirit.  The seven-sealed book will be complete in the consummation of the opening of the seven seals and the blowing of the seven trumpets which will be blown when the seventh seal is opened.    

Ten:  Is the indefinite number or a round number, a number subject to change:  Ten virgins, ten days.

Twelve:  The redeemed number.  The twelve tribes  in the Old Testament, in the New Testament is the twelve apostles, in the Holy City are twelve gates and twelve foundations stones named for the saints of the Old  and New Covenants.