custom function changes datatype during run time

In power query I got a custom function which picks up the data, does left join and returns the records properly. The tables are linked using t1.c1 and t2.c2. the data type of both columns is Text. It is tested using sample data file used for the function. When that custom function is called from some else place (i read all files from a folder and call the function for each of the file)...the function works correctly except for the data with last digit as zero. e.g. "01.10", "01.20" in this last value is zero wherein for t1 the value is automatically converted as "01.1" and in T2 the value is retained as "01.01". Bu then records doesn't get linked as the data alues are different. Please note, in both the tables field's data type is text, but it seems still it trims out zero from t1.c1 but not t2.c2. Also within custom function it seems to be working fine, but when caller makes the call to the function it doesn't return matching records. Any idea what could be the issue?