Hi there! 

Could you provide me with the time you think it should've taken? Or perhaps the formula you're using? 

Maybe there's an error that confused you.

Hello, lord!

Here is an instruction how to report bugs. There you will find the optimal format for reporting bugs. In addition to that, there are two core points: 

- Coordinates of your Castle and name of the platform (Facebook or plarium.com).

- Way to Reproduce the Issue - it will help us understand what you expect to see (expected result) and what you actually get (actual result).

In this way, we will avoid misunderstandings and handle your case much faster.

It takes 15 hours to cook 300 archers without Obelisk of Power or boosting (3 min each).   Dwarves will obviously take longer.

It appears your archer build time was approximately 132s.  220 archers at that rate would take 8 hours 4 min.   80 dwarves, with an average build time of 4.5 minutes, could be built in the next 6 hours to make a total of 300 units in 14 hours.   I presume your 25% dragon infantry boost was active during the screenshot, bringing the archer build time down to 132seconds.  Since you only had it active 6 hours out of the 14 hours...less than half the time, the archer build time was likely much longer than 8 hours 4 mins, which would then lessen the needed dwarven cooking time to much less than 4.5 minutes to achieve the 300 total in 14 hours., as you said your max was about 4 minutes without the dragon stone.

Based on information provided:

25% boost for 6 hours should give you about 164 archers.  You had 220 archers in queue, meaning 56 more to go, including 80 dwarves (for 300 total infantry), without boost.

The 56 archers would have taken about 2 hours 48 min to complete.

The 80 dwarves would have taken about 5 hours 21 minutes to complete.

Your 300 units should have taken approximately 14 hours 9 minutes to complete.

Your training times seem on target to me.