Result coming back as text not a number.....maybe?

Maybe try this:

Formula:

=IFERROR(IF(ISNUMBER(SEARCH("PK",A5)),VLOOKUP(LEFT(A5,SEARCH("PK",A5)-1),TDM!A:CC,28,0),

IF(VLOOKUP(A5,TDM!A:A,1,0)=A5,VLOOKUP(A5,TDM!A:CC,28,0),0)),IF(ISNUMBER(SEARCH("PK",A5)),VLOOKUP(LEFT(A5,SEARCH("PK",A5)-1)+0,TDM!A:CC,28,0),

IF(VLOOKUP(A5,TDM!A:A,1,0)=A5,VLOOKUP(A5,TDM!A:CC,28,0),0)))

Original formula could be just this:

Formula:

=IF(ISNUMBER(SEARCH("PK",A3)),VLOOKUP(LEFT(A3,SEARCH("PK",A3)-1),TDM!A:CC,28,0),

IF(VLOOKUP(A3,TDM!A:A,1,0)=A3,VLOOKUP(A3,TDM!A:CC,28,0),0))