I understand, but the Jan-18 have to be in the dashboard to show up right? The value Jan-18 doesn't exists in Month Year field... may be you can create it using a master calendar where you have one extra month... but you need Jan-18 under Month Year to make this possible....
Just to show as an example... I added it like this
Month([Created on]) as [Created Month],
MonthName([Created on]) as [Created Month Year],
"Actual End Date",
FROM [lib://Lib/Need Help.xlsx]
(ooxml, embedded labels, table is DATA);
LOAD MonthName(MakeDate(2018, 01, 01)) as [Created Month Year]