I suggest you check the rounding requirements of your tax authority and do what is necessary to comply with that.
For example, in Australia the ATO specifies how rounding must be done at the line item and invoice level when calculating GST. Both suppliers and customers must comply with these requirements. However the specifications allow a some flexibility in internal precision used in accounting software and as a result the supplier a customers calculated GST does not have to be the same as long as both comply with ATO requirements.