John,
What about the size of these blocks? What on Earth are they doing!
FB60 itself is 5740 bytes, and it calls (wait for it!) FCs 1,3,7,12,18,23 and 35 from the IEC Library. FC1 and FC35 alone are over 1500 bytes each, the others are all around the 300-500 byte mark. That's getting on for 10Kbytes, just to change a clock. Ye Gods, and little fishes - there might just be room left for a small program beside that!
Ken