The GM OS does not have table B3647...
When you install the COS, it replaces B3605 (which is ECT x MAP) with B3647 (which is RPM x MAP), and it retains the old data that B3605 contained...
so your new B3647 looks like the old B3605, but because the vertical axis now RPM (instead of ECT), the data in this table is not completely sensible, you have to edit it (see my suggestions above).
i.e. B3647 occupies the same space as B3605, but it changes the vertical axis from ECT to RPM, so the ECT x MAP data is not valid, you have to edit it into sensible RPM x MAP data.