Unfortunately, this introduces an additional level of complexity, so bugs are very likely.
I found when (daily) Notes is enabled and new time entered in Week View, the content of the Week Note is not used (presumably because the Week Notes content is used). In this case, showing the Week Notes box will be confusing for users because they will not know from the UI where notes should be entered.
Also, Week Note content _is_ used when (daily) Notes is disabled, which may be confusing due to the interaction of configuration settings.
What if "Week note" and "Notes" were mutually exclusive with a single "Week note" enable/disable configuration. If (daily) Notes is enabled, Week Note is hidden, and if (daily) Notes is disabled, then Week Note is shown. What do you think?