IB Recurring Investments: Avoid tiered pricing?

As far as I know, this is not a general rule. You will get a 1% fee on the fractional part only. For instance, if you buy 5.4 shares, you will pay the standard fee on 5 shares and then a 1% fee on the 0.4 share. Again, I think this only applies to European stock exchanges. So, it should not matter much, but I have not tried since I am not automating my investments.