Tire Sidewall problems of the 1999 BMW 323

All 5 original tires had sidewall splitting/herniation (including the spare), other instances were reported to me by peake BMW (I. E. 15 to 20 other sets of tires were replaced for a discount as under warranty). I am concerned by these numbers and the fact that they will not pay 100% to replace the tires. I am also concerned as to how they report this data and whether they are collecting the data in a manner sufficient to determine whether a recall is warranted. (dot number: 205 tiresize: 205/55r16c).