PowerBI DAX to lookup in another table between two dates

Hello all you beautiful people!

With lots of googling- still cannot solve this simple PowerBI trick. I want to build another table based on two tables - for timesheets - of which one table has the start and end dates of the timesheets month, and the other the timesheets themselves. I want to get a column added to the timesheet to state in which timesheet month it falls. (Timesheet month end is a few days before month's last date, based on day of the week, etc)

Example tables:

Table cfgTimesheetMnth:

Table erpPrjTimesheets :

Results Table. I then want to build a new table in PowerBI that needs to look as such:

Table verpPrjTimesheets:

The code in the dataview in PowerBI I started with are:

verpPrjTimesheets = 

VAR t1 = SELECTCOLUMNS(erpPrjTimesheets
            , "EmpNo"    , [EmpNo]
            , "tsDate"   , [tsDate]
            , "Hrs"      , [Hrs]
            , "tsPeriod" , LOOKUPVALUE(cfgTimesheetsMnth[Period], cfgTimesheetsMnth[tsDateEnd], erpPrjTimesheets[tsDate])
) RETURN 

t1

But the LOOKUPVALUE does not have a command to lookup between two date ranges. So above does not work.

What would be a better approach?

Here you go.

verpPrjTimesheets = 
ADDCOLUMNS(
    erpPrjTimesheets, 
    "tsPeriod",
    SELECTCOLUMNS(FILTER(cfgTimesheetMnth, erpPrjTimesheets[tsDate] >= cfgTimesheetMnth[tsDateStart] && erpPrjTimesheets[tsDate] <= cfgTimesheetMnth[tsDateEnd]), "tsPeriod", cfgTimesheetMnth[Period])
)