Honestly I could show you a gazillion sample images where the borders are poor at 70mm. Visually I would also rate the results as shown in the review.
We do not measure the tangentially and sagittally resolution independently nor does this may any sense from a non-academic perspective. We are looking for the combined maximum of those two values. Thus the result doesn't have to be on the same focus plane as the center (which is, in fact, rather rare). This is also how we can make statements about field curvature - thus the relative distance (Z-axis) of the local maximums between center, border and corner.
We do not measure the tangentially and sagittally resolution independently nor does this may any sense from a non-academic perspective. We are looking for the combined maximum of those two values. Thus the result doesn't have to be on the same focus plane as the center (which is, in fact, rather rare). This is also how we can make statements about field curvature - thus the relative distance (Z-axis) of the local maximums between center, border and corner.