Setting up historic rates

Summary

Need help setting up and managing historic rates using spreadsheet

Content

Hello,

We are in the process of implementing Oracle cloud and we are trying to set up our historic rates in our test system and they do not seem to be working like expected.  I have been unable to find clear instructions on how to use the spreadsheet and how each of the options would affect my choices. 

Can anyone confirm the effect of the rollforward column...based on my testing it appears that if this is set to NO the rate only lasts for one month and then reverts to the entire amount being converted at the period end rate and we should most likely choose YES - is this correct?