lvchange -r 256 lv-name does not work

Hi , i came across a problem with lvchange command.

I have a VG with 3 pv and a lv created using command

lvcreate -i3 -I32 -l98 -nmy_lv my_vg
lvdisplay shows 1024 as the value for Read Ahead Sectors.

When i use the command lvchange to change the value of read ahead sector with value more that or equal to 256 i get following error..

linux# lvchange -r 340 /dev/my_vg/my_lv
lvchange -- ERROR "Invalid Argument" read ahead sector change linux#
linux#

Is there a limitation that read ahead value cannot be greater than 255?

Thanks
-Sachin