[j-nsp] OSPF question

[james list]

Dear experts,
a customer of mine has the following OSPF scenario:

  .........................................................
  .                                                       .
  .   area0      area10 totally stub           .
  .       |                 |                              .
  .       |   +----+ DR   |                             .
  .       |---|RT1|--------|                              .
  .       |   +---+        |                              .
  .       |                  |                               .
  .       |    +----+      |                              .
  .       |----|RT2|------|                               .
  .       |    +----+      |    +------------+           .
  .       |                  |----|host5/6/7|            .
  .       |      +---+     |    +------------+            .
  . DR  |-----|RT3|-----|                               .
  .        |     +---+     |                               .
  .        |                 |                               .
  .        |      +---+    |                               .
  .BDR |------|RT4|----|                               .
  .        |      +---+ BDR                           .
  .        |                                                .
  .                                                         .
  ...........................................................


Four MX routers RT1, RT2, RT3 and RT4 running OSPF as ABR (area 0 and area
10 totally stub), on area 10 there are some host talking OSPF (host5/6/7 in
reality are more).

On MX side I see a lot of OSPF retransmissions on area 0 expecially on the
DR-other (RT1 and RT2), I guess it’s due to the following:

1- Host 5 or other send LSA update to all routers on area 10 (RT1, RT2,
RT3, RT4)
2- All routers advertise the update to all the others routers in the same
Ethernet segment
3- If for example RT1 and RT2 simultaneously send the same update towards
RT3, RT3 will send the ACK only the first it gets (let’s say from RT1)
4- So RT2  will wait for ACK, put LSA in the Link State Retransmit List and
after 5 seconds (default LSA retransmit interval), RT2 retransmit to RT3
5- After retransmission RT2 get the ACK from RT3

Am I wrong ?
Does it sounds as reality ?
Should I expect instability, which the customer did not get till now ?

Cheers
James