How to amend one variable in a Full Factorial Design during experimentation

I have a 2 level, 4 factor DOE set up for 16 runs. These are all continuous factors. I'd like to amend one of the factors to a narrower range. I am currently 10/16 runs complete and am wondering if there are any options available before I have to end up repeating the first 10 experiments. I looked into folding, but I'm not really sure if I can apply that (blocking effect from different weeks, equipment, etc). Are there computer designs that could amend the original design and produce a comparable design resolution?

Any help is greatly appreciated!
The range was made too wide and was studied previously. The purpose of the experiments was to narrow the ranges for better understanding of the process.
I'd also be interested to know how to widen a range in the middle of a full factorial DoE assuming blocking is necessary. Just in case something similar happened. I'm not sure if that's easier or harder.


TS Contributor
If you change the levels part way through the experiment, you should be able to analyze the experiment using GLM or regression. However, the experimental design is no longer orthogonal nor balanced, and there are repercussions associated with that. The most obvious is the loss of power. While you will probably still detect strong effects, you will likely miss all weak effects and a percentage of moderate effects. If you are trying to build a model and optimize, your model will not be as good and your optimization off as a result.