Ann: Next cohort reached in IV arms of CF33-hNIS (VAXINIA) study, page-9

Sounds more like they wanted a larger N value (population) for the monotherapy.
I imagine this could then be used to help inform future combo trials and allow them to start at a higher rate, particularly for IV where they've mentioned it needs more virus due the distribution that occurs.

it would seem that the initial dosage rates planned from the start can be increased without negative effects and they want to explore it further.

I don't see why it needs to be taken negatively, adjusting trials to get greater clarity and more data that is useful for the future seems like a good plan.