Differences between graphs and maths

[ianwaugh@xxxxxxxxxxxxxxxxxxx (Ian Waugh)]

I've been experimenting with Bollinger Bands (9 period, 2 Stdev), with 
setups which trigger when the high or low or close is above or below a 
band.

The calculations seem to work correctly and the Data window confirms this  
but the graphic display with the BBs drawn on doesn't always seem to 
show this correctly. For example, the calculations might show the low 
below a band but in the graph it might be slightly above. This makes 
eyeballing the patterns impossible.

Has anyone else experienced this with any indicators? Comments, 
suggestions?

Running TS 4, latest update on 21" monitor at 1152 x 864 16-bit colour.

Cheers,
Ian