I've also looked at it and it turns out that I had to use the "Burn Bootloader" feature in IDE 1.0 which for a Tiny simply means that the fuses are burned correctly. Until then the timer was not setup correctly. Also I've switched to the internal 9.6MHz calibrated oscillator is the timing is perfect now. Here are the fuses:
attiny13.bootloader.low_fuses=0x7a
attiny13.bootloader.high_fuses=0xff
Please note that I'm sort of integrating your core with Demellis'es . I honestly could not find a way to burn the fuses with yours - the bootloader file was missing or I simply failed to find it. How'd you do it?
Cheers!