What code is causing number field format error on Rate Set Target page after changing Rate Amount?

PeopleSoft Project Costing 9.2 on tools 8.59.16.

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Using a rate set/target with a To Currency of JPY. In the currency setup, JPY is set with decimal positions of 0. I change the rate amount value to 1.21 on a line with Rate Option of MUP and get the error on save.

The full error is "Number field format error. The field format is (23.0). The currency control field TO_CUR restricts it too. The value of the currency control field should be the name of a currency entry in the PS_CURRENCY_CD_TBL, which defines a currency symbol, thousands delimiter character, decimal character, integer positions, decimal positions, and scale positions. The value for this field is constrained by the more restrictive of that format and the field's format."