I have written model.time to two different token labels, and I hope I could write down the token label value when token on entry each activity, at the same time calculate the time between start and ends in third column. I test another example from this forum, I found that there's no problem if the value I'm recording in statistics collector is a label value. Now I try to record the time information, then there's red triangle on left top of a cell, may I ask what this means?