Initial Value based on Max [Timestamp]

[MauriceWhelan]

Hi.

I have a column [AM/PM Charge] in Table Operations_Master_Check and I want the initial value of this to be the same as the row in the table with the MAX() [Pre-Treatment Timestamp]. This MAX() timestamp is not necessarily the maximum row in the table so I cannot use MAXROW(). I tried a virtual column with App Formula MAX(SELECT(Operations_Master_Check[Pre-Treatment Timestamp],TRUE,TRUE)) and set the initial value in the [AM/PM Charge] column to [Max Pre-Treatment Timestamp].[AM/PM Charge] but I am getting the following error.

Column Name ‘AM/PM Charge’ in Schema ‘Operations_Master_Check_Schema’ of Column Type ‘Enum’ has an invalid Initial Value of ‘=[Max Pre-Treatment Timestamp].[AM/PM Charge]’. Error in expression [Max Pre-Treatment Timestamp].[AM/PM Charge]

Any help in the right direction on this would be great, thank you.