I have found that it is possible to have field names with spaces, periods, or other special characters if that special character is preceded by the JavaScript escape character, "\".
The simplified field notation is actually a front end that gathers the field names, operations, and variables, parameters to the function, to be used a built-in JavaScript function to perform the calculation using JavaScript. So just like in JavaScript, one needs to use the escape character to inform the function to pass the next character as part of the field name to be processed and not as character separating one parameter from another parameter being passed to the function.
You could try:
BoCC\ BudgetRow1 – YTD\ TotalRow1 – Budget\ BalanceRow1