Valdemar timeline confusionFollow

I've been rereading some of the Valdemar books recently and there's a timeline inconsistency that's bothering me.

When exactly did the Tedrel Wars happen compared to the rest of the books that take place during Selenay's reign?

Exile's Valor says that Elspeth was born about 2 years after the war ended, and at the start of Arrows of the Quest, Elspeth is 7 years old. This says to me that the war was 9-10 years earlier. However, Arrows for the Queen also says that the war was 15 years ago, and Take a Thief (which happens a 3-4 years before Arrows of the Queen) says it was 20-30 years ago.

Does anyone know which version is right?