After play with this mod then install other mods like power armo mk4 and other, the craft speed go back to orignial, i tried to delete and installed again. The craft speed still at oringial speed even i update the research to 21. The speed is still very slow!

Unfortunatly, i had the same problem. I removed speed research mod, loaded game, installed it again and everything works but you have to research everything again, sadly.

i made a fix
replace everything in the control.lua in the factorio mods folder, type "%appdata%" in run and open factorio, and in factorio the mods folder, then inside craftingspeed research, replace everything with this:
Note: this will reset the crafting speed to what it should be everytime you research so lvl 23 will become 23*0.2 + 1 = 5.6 and if you set it to something else with a command, all you have to do is research it one more to to get the right value back.

script.on_event(defines.events.on_research_finished, function(event)
local research = event.research
local force = research.force
local name = research.name
if name:find("crafting%-speed%-upgrade") then
local mult = tonumber( string.sub(name , 24))
if(mult > 20) then
mult = research.level
end
force.manual_crafting_speed_modifier = 1 + 0.2 * mult
end
end)