Indeed, the conventions used to normalize the dSPM values changed a few times in the past years. None of these values are wrong, but the conventions used behind are different. See the news feeds and the current documentation:
https://neuroimage.usc.edu/brainstorm/News#July_2018
https://neuroimage.usc.edu/brainstorm/News#April_2015
https://neuroimage.usc.edu/brainstorm/Tutorials/SourceEstimation#Averaging_normalized_values
Averaging dSPM values is tricky, and so far we were not keeping track properly of the effective number of averages needed to weight correctly various dSPM values. The dSPM implementation itself should not change anymore, but we are these days finishing a clearer interface around it. We will be more explicit in showing that the new values you obtain (1.2) need to be multiplied by sqrt(nAvg) to obtain a proper dSPM values. The pull request for this change is currently under review on GitHub:
https://github.com/brainstorm-tools/brainstorm3/pull/212
We apologize for these inconsistencies, this is not an easy question to address in the context of a generic platform like Brainstorm. We hope this will stay stable in the future.
If you think this needs better online online documentation (the section in the source estimation tutorial), please share your suggestions.