Why does this Friday 13th program fail?

[Joe Horn]

Perusing old postings I ran across several "Friday The 13th" programs, and whipped up this obvious-ware for the HP Prime. Looks to me like it should work. But it doesn't.

Code:

EXPORT FRI13(Y)
BEGIN
LOCAL j;
L9:={};
FOR j FROM Y+.0113 TO Y+.1213 STEP .01 DO
IF DAYOFWEEK(j)==5 THEN L9:=CONCAT(L9,j);
END;
RETURN L9;
END;
END;

An input of 2017 should return {2017.0113, 2017.1013}, but it only returns {2017.0113}.

An input of 2026 should return a list containing 3 dates, but only an empty list is returned.

What am I doing wrong?