I've noticed, after attempting to do some zone system calibration, that the shutter times on my 80 CF seem to be long by 25-50%. What's the likelihood that the faster times are also off? Is there anything I can do, or is a CLA the only option. If I need a CLA, is there a relatively inexpensive place to get it done? I only paid $250 for it as it's got some coating marks and I can't afford the $200 to have it done by David Odess.