Dear Jay,
the order of columns in your design matrix does not really matter for the estimation of effect sizes. There has been a change in SPM a long time ago which shuffled around design matrix columns. Also, it may matter (in a sense of column order, not in effect size estimation) whether you specify a "Regression" model or a factorial model with covariates. Therefore you may encounter different design matrix layouts when reading different tutorials. SPM fits the model at once and has no special treatment for covariates "of interest" or "of no interest". Your contrast picks the "Performance" effect as you intended, so you should be fine.
Best,
Volkmar
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