Try using phasor~ with snapshot instead of metro. If you have a lot going on, metro suffers from the limit of messages per block... someone in #max/msp on efnet was explaining this to me. using phasor~ locks the speed of your counter to the samplerate, which is consistent, whereas sometimes messages can be delayed a block if there's too much going on. i think so anyways, i might be wrong, but it's an option.