I think the Olympia 2200 is the same machine as the JCM 2200; same machine, just marketed under a different name. If that's the case, the following procedure should work:
1) Turn the key to 'PROG'
2) Enter a 1
3) Enter the rounding factor. This will be either a 0, 5 or 9. A 0 causes fractional tax amounts to be rounded down to .00 . A 5 causes fractional amounts of .001 to .004 to be rounded down to .00, amounts of .005 to .009 to be rounded up to .01 . A 9 causes fractional amounts to be rounded up to .01 . In most cases you will use a 5 unless your taxing authority dictates otherwise.
4) Enter the tax rate as 5 digits with three decimal digits assumed. Ex. 6% would be entered as 06000, 12.5% would be entered as 12500 .
5) Press the TAX SHIFT key corresponding to the tax rate you wish to set. Generally, this will be TAX SHIFT 1 for tax rate 1. However, you may have a TAX SHIFT 2 and/or 3 on your keyboard if you use multiple tax rates. Use the key appropriate to the rate you want to set.
Good luck ...