A question for you would be: how often does your replication scheme replicate between the publisher and subscriber? If memory servers with merge replication, the threshhold is only really checked / updated when the replicated servers merge with each other. So, if your servers merge once a day and you've reached 85%, the new identity range will be issued when the merge happens.
A way to check the current identity range of your table... go into enterprise manager design view for the table, and go into the constraints information. The identity range should be defined here.