Question the amount of HP a player will respawn

[* Blaze * 6]

Player.conf setting

// The amount of HP a player will respawn with, 0 is default.
// (Unit is in percentage of total HP, 100 is full heal of HP, 0 is respawn with 1HP total.)
restart_hp_rate: 50

// The amount of SP a player will respawn with, 0 is default.
// (Unit is in percentage of total SP, 100 is full heal of SP, 0 is respawn with 1SP total.)
restart_sp_rate: 50

How to set On respawn, 50% of Max HP/SP will be restored.??

When i try to set restart_hp_rate: 50  the formula not working any idea how fix restart_hp_rate & restart_sp_rate? im using old revision thanks