The type of lien is determined by what the current value of the vehicle is as it sits today. If it is under $4000 then you choose an under $4000 lien and if it is over $4000 then you choose an over $4000 lien.
Please note that if you submit the request as an under $4000 lien that at the end of the lien process you will not be able to sell for more than $4000. If you do sell for more than $4000 any extra money must be forfeited to the California DMV.