Trenbolone acetate has a pretty short half life, only 3 days, which means that after an initial inj, 3 days later you have half of that amount left in you. When you inject, blood levels fall rapidly, then spike again after next injection. With an ed injection you get another administration of the drug before the previous administration drops too far. Therefor you get a smoother increase without the drops.
Keep in mind, the timeline on the above graphs is days. If I were to calculate blood levels on an hourly basis and plot 24 hours in a day for 20 days, the ed injection would also show peaks and valleys which are not seen only plotting blood levels daily. These peaks and valleys of course would still be much much smaller that the eod injections though.