How "reliable" are the ship dates for US Based Retailers for Pre-Orders?

Wow that was a mouth full. Anyways, long story short, I wanted to purchase a few figures from a US based retailer instead of a Japan one for Reasons. The two stores in question are Crunchyroll and Anime-Island. I may have jumped the gun on the pre-orders, but what is done is done.

Anywho, how reliable are the Ship dates that they present? Are they known to be somewhat accurate or should I tack on an additional month or so??

Thanks!