IMHO: yes, from personal experience with mixed 15 and 14 lbs. equipment for some time. That pound more or less is recognizable esp. in the downswing and final release - I used to loft the lighter balls a lot, the downswing became quicker (I put some muscle in the swing's end phase) and that threw timing off.
Nothing that could not be fixed with training, though, but starting such a mix for a tournament is IMO not a good idea. Just using one weight class would IMO not cause that much of a problem, e. g. only 15 or 16 lbs. Mixing them bears larger risks.
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DizzyFugu - Reporting from Germany
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