Good eye! You are correct that the ballast reference is only to the increments, but there's no mention of any maximum. It seems that some of us (me included) at some point started (mis)quoting that section of the rules when in fact there was no maximum allowed ballast amount.
Citing Section 1316.B.4(a):
"4. Weight and Ballast
(a) A minimum weight for cars with driver will be honored at all
times. Ballast is allowed, but must be located on the
passenger floor, aft of the firewall and no further rearward
than 1” of the rear stock seat bolt holes of the front
passenger seat. Ballast shall be in segments no heavier
than 50 lbs, and shall be capable of being removed to be
weighed apart from the car. Each segment shall be fastened
securely to the floor with a minimum of two (2) bolts, SAE
grade 5 or better with locking nuts, with large-diameter, load
distributing washers.
E30 325i minimum with driver is 2,650 lbs."
The complete comp regs may be found at:
http://www.icscc.com/rules/comp_regs_2009_complete.pdf
Feel free to email me direct for any questions as well. rickshaw_racing at yahoo dot com.