FYI,  

The order in which your permissions are stored in config matter for Permission Multipliers.  If you have multiple ranks, permissions, aka groups, configured with different multipliers as shown below, the first permision in the list shown below that a player is assigned to, is the one that the player will use as their multiplier.

For example, if a player has all 3 permissions assigned to them as shown below, they will have the Workhorse multiplier.

"5. Permission Multipliers": {
"default.vip2.workhorse": {
"SetPermission": "default.vip2.workhorse",
"Multiplier": 2
},
"default.vip1.achiever": {
"SetPermission": "default.vip1.achiever",
"Multiplier": 1.5
},
"default": {
"SetPermission": "default",
"Multiplier": 1.0
}

However if a player is configured the same way, having all 3 permissions assigned to them, they will receive the Achiever multiplier.  This matters if you're attempting cumlative permissions.

"5. Permission Multipliers": {
"default.vip1.achiever": {
"SetPermission": "default.vip1.achiever",
"Multiplier": 1.5
},
"default.vip2.workhorse": {
"SetPermission": "default.vip2.workhorse",
"Multiplier": 2
},
"default": {
"SetPermission": "default",
"Multiplier": 1.0
}

For example, if you're using Better Chat, the priorities of Better Chat do not apply.  So if Workhorse is supposed to get the higher multiplier, the Workhorse permission will need to be at the top of the list, as shown in the first example above.

In addition, you'll want to grant the Group associated to your multiplier permissions under playtime rewards.

usings Permissions Manager, in game, in chat...

1. Type /perms in chat in game.
2. Select "All Groups" to edit your groups.
3. Choose a group that you have configured to have a multipler.  Example: default for people first logging in.
4. Under Permissions for Default, the next screen, select playtimerewards
5. Only select Granted on the group you want to have rewarded.