This is dangerously outside my comfort zone, but from what I understand of mechanics I think you could see a circularizing effect (with rising perikerb) from drag even with no deflection lift, provided that there is a significant radial component to the entry velocity vector. It seems likely that this could be so in the case of a highly elongated 600-to-entry orbit. I\'m thinking of it in terms of mechanical work. At first glance, it seems obvious that any work from a pure drag force must always occur exactly along the orbit, which should only reduce the perikerb. However, entering and exiting a spherical atmosphere may change that. I choose to ignore the variation in atmospheric density because a. it makes my brainmeats quiver and b. I think it may actually favor circularization but is at worst irrelevant in the case of pure drag. Let\'s consider the work done on the capsule during the first half of the 'burn', to perikerb, and the second half back out to space. Consider the transit times in and out to be effectively equal for the sake of argument. This is the shakiest step in my chain of logic; obviously the outbound trip takes longer, but I\'m assuming that this increase is dominated by the decrease of the v2 term in the drag equation. Provided those assumptions, the work done on the capsule is greater during the inbound trip than the outbound because the magnitude of the velocity has been reduced before the outbound half. Thus, there is a net outward radial component to the work done, equivalent to an outward radial burn, raising the exit angle from what it would have been without atmosphere and thus increasing the next perikerb. (edit: ...and causing a retrograde shift in the argument of periapsis, which we\'re not currently well set up to measure but which could theoretically verify whether I\'m full of crap.) This phenomenon would, of course, never raise perikerb beyond the atmosphere and would become less and less significant as the orbit became more circular with shallower entry angles.
