When you turn off calculation, it also turns off the chart updates.
Also, when you turn off calculation, it would affect all the
calculated min/max/avg values.

You might be able to turn off the calculations, update all the values
from your market data source, then turn on calculations (this would
update the min/max values you might be using to determine your chart
ranges), then update the chart. If you have a bunch of series to
update, you might want to turn off automatic calculation, then just
force a manual calculation after retrieving the data, update all the
series, then turn on automatic calculation again. The code for the
chart would be something like this...
ActiveChart.SeriesCollection(1).Formula = "=SERIES(Sheet1!
R1C2,Sheet1!R3C1:R6C1,Sheet1!R3C2:R6C2,1)"
By the way, what are you using for your market data source? I've
never gotten Bloomberg to update that quickly.