Is ESA Contributory notional income for IS

Hope someone can clarify this, have a client who is within 11 weeks of expected date of confinement, she wants to claim Maternity Grant but is in receipt of ESA cont so doesn’t get a qualifying benefit.

JCP have advised her to claim IS instead, client doesn’t receive DLA so would be entitled to basic rate IS only which is less than her ESA but she would get her maternity grant. If client swaps claims would IS treat her contributory benefit as income she has deprived herself of in order to claim means tested?

Im aware this is not a direct answer to the query as put, but if the issue is getting a SSMG, couldnt she claim it once the baby is born and she gets more than the family element of CTC?  Ofc it depends on getting more than just the family element, but if IS is being considered as a possiblity, Im guessing she has no other sources of income/capital. At least this way (if poss) would mean she can get the grant and stay on a higher level of income?

Thanks for reply, have considered this as also thought if takes a while for IS claim to be processed she would at least have something to live on.
My concern though is depending on which DM gets claim they may think her contributory benefit should take priority over means tested and she has deprived herself of this in order to become available to a means tested benefit (which she has)