Yes, RM150 is the exact amount to be remained in the credit balance.  RM6.19 should be transferred into your bank account already by yesterday but the amount transferred is based on the extra amount from your total credit balance by the day which incentives credited.

E.g. Incentive credited on Tuesday or Wednesday night is RM100 whereas your credit balance is RM120, make up a total of RM220.  On Thursday, you receive jobs and credit balance is being deducted RM20, the total becomes RM200, but on Friday, Grab will still deduct RM70 and transfer to your bank (based on total credit balance on Tue/Wed) so after deduction, sometimes you may see your credit balance <RM150 i.e. RM130 in this case.