MetaStock ADX vs. RealTick ADX

I'm looking at using the ADX to select between a Stochastic and a
moving average crossover system as appropriate for trending vs.
channeling/cycling conditions.

Can anyone shed some light on the difference between the ADX
indicator displayed in RealTick and the ADX function in MetaStock?
When I plot them on the identical price data in the two different
software packages, the results are completely different. The
RealTick ADX behaves as I would expect, with significant variations between higher values (> 30 or so) for trending conditions and lower values (< 30 or so) for channeling conditions. The RealTick ADX line also begins 14 days after the start of the data for a 14-period ADX. The MetaStock ADX is nearly a flat line, and begins 28 days after the start of the data (for a 14-period ADX). It looks like it's being smoothed a second time.

I've done some investigation but have not yet done a spreadsheet to re-creat Wilder's formulas from his "New Concepts in Technical Trading Systems". That's my next step, but I thought someone else may have already figured it out.

So far it looks to me like it's a difference in terminology - that
the ADX in RealTick is actually Wilder's DX, or the MetaStock DX is
actually Wilder's ADX. I also note that MetaStock's custom formula
library includes a custom indicator which calculates ADX and ADXR
without rounding, with the note that the built-in indicator is exactly the same as Wilder's original calculations. I wouldn't think
that the rounding difference would be large enough to account for the difference between the two software packages.

Thanks.

Gary
 
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