What do you mean by "High Quality" though? Who decides its post quality? If its the bctaccountpricer.info stats, well the bot only seems to check the post length and post quality is something that is highly subjective.
High quality = Almost all posts are only constructive posts. No spam
The website you provided in the link is down.
Sorry its this: bctalkaccountpricer.info . As for the quality, could you provide some additional details like Average post length, post count(fairly estimated to avoid getting the account found out) by board and if its currently enrolled in/rejected by any campaign. All of the details might seem necessary as your main "point" in high account price(BIN) seems to be because of mostly post quality. All of these might be avoided if you get a neutral party like master-p who don't care about the marking an account based on its ownership.
Is there any site that calculates average post length?
I have provided an estimate on the OP.
What do you mean by "All of these might be avoided if you get a neutral party like master-p who don't care about the marking an account based on its ownership."?
The site I have provided gives what you require but the second option is better considering it will be done by a human instead of a bot. What I meant is someone like master-p can be used who regularly escrows account sales, and never tags any account based on transfer of ownership , can review the post quality and post his "vouch"/his opinion on the post quality.
If majority of the posts are no topic and constructive then it is considered as good-post quality,
however the same post is excellent if it posted in very good english (probably by a native).
master-p is an escrow not a PhD in literature.