@jjg..well, $19,798 is pretty much 20K in my book (according to rounding rules), but it is a minor point....that you seem to be awfully sensitive about.
BTW, the average price of btc between Dec 2017 and today is also quite surprising (not!) $20.3K...how does this reflect on DCA vs bulk purchase debate?
Basically, you could have DCAed weekly since 5 years ago (or 260 weeks) and your average would have been more than btc price just a month ago (only 4wk or 1.5% of the putative DCA time).
This shows, in my opinion, that better strategy in bitcoin is to have a large stash of cash and to wait for more than 60-70% decline from the recent ATH, then pounce at once or in a few big "gulps".
Rounding rules? that is not how it works in economics. Either something has hit $20000 or it has not. You cannot round up values rounding up is only done to estimate something but is not used for speculation because it would skew the numbers to much and any speculation or prediction based on rounding up will be greatly wrong even if they have a good argument. Do not round up unless you are estimating small numbers when it is big numbers like 20000 you will be greatly out of any prediction or analysis.