The world isn't black or white. The Method was designed to recognise shades of grey so, for the Needs Matrix and Service Scorecard, embrace decimal places.
If an organisation has three core objectives which they say are equal weight, you have decimal places by default.
If you conduct quantitative research in order to determine values for the Method, you are very likely to have decimal places in your data.
You can use decimal places in the Initiative Scorecard but the value ranges here were designed for simplicity and ease of use. It will be an easier process if you stick to the five-point scale.