广播参数设置，BroadcastDeliveryTime，PassiveAckTimeout和MaxBroadcastRetries是什么关系？

在nwk_globals.c文件中，有以下提示

  // BROADCAST SETTINGS:
  // *******************
  //   Broadcast Delivery Time
  //     - set to multiples of 100ms
  //     - should be 500ms more than the retry time
  //       -  "retry time" = PassiveAckTimeout * (MaxBroadcastRetries + 1)
  //   Passive Ack Timeout
  //     - set to multiples of 100ms
  _NIB.BroadcastDeliveryTime = zgBcastDeliveryTime;
  _NIB.PassiveAckTimeout     = zgPassiveAckTimeout;
  _NIB.MaxBroadcastRetries   = zgMaxBcastRetires;

BroadcastDeliveryTime设置要比 retry time多500ms，那么retry time的计数单位又是多少？按照公式，PassiveAckTimeout为5，MaxBroadcastRetries为3，那么retry time就是20，是不是BroadcastDeliveryTime最小为520ms？