Laserfiche support both IF and AND with formulas

Syntax would look like this

=IF(OR(Initiator=User1,Initiator=User2),TrueValue,FalseValue)

=IF(AND(Initiator=User1,Initiator=User2),TrueValue,FalseValue)

To get the Current User of the Form takes a little more work.

This post will show you how it can be done to capture the current step on a form. Use the same technique but just with the CurrentUser variable instead of the Step.

https://answers.laserfiche.com/questions/113428/Accessing-the-Name-of-Task-Step#164170

The way I might approach this is to create a Hidden field in the form which has those users name

Field: ShowUsers

FieldValues: MaryJaneDoe,JohnSmith, etc     (using their username)

Field:ShowForm

Then use a Formula with FIND to see if the Current User name you captured above is in this list and if the CreditType is Credit.

=IF(AND(PaymentType="CREDIT",FIND(Current UserValue,ShowUservariable,1)>0),"Yes","No")

The way FIND works is if it found an exact match anywhere in the ShowUser field it returns the position of where the first character was in the string. If it found a match then the position will be greater than 0, if not found it return nothing

You can then use this Field Value in your field rules to display what you want

The reason I do it this way is as the users change I can just update the ShowUsers Field without having to change any Rules or the Formulas themselves

Might look a little complicated to set up but will pay dividends down the road.