After creating the trade to others for training, if they accepts it for training, there should be a option to them for the borrowed pokemon like this,
slot:6
required training: 1 bil or 1,000,000,000 exp
time: selected

if its like this when that pokemon in 6th slot, gains 1 bil exp, then it must return to the owner if the time is not over also. Not even one extra exp also.
example: If he selected 100 bil exp, after gaining that exp the pokemon must return to the owner. And the extra exp will given to the previously used pokemon. Rate and comment it if its not really doubtful, post questions here...! Thanx for reading this.

Nice idea, will help us not overtrain other's pokemon. But, we don't mind doing a little extra training for someone... at least i won't find it helpful, lets see what others think.

Its helpful to train all pokemons a same level or to battle snorlax towar we need some same leveled giratinas so we do nice..!

Great idea :)

personally i dont like it, i sometimes loan myself my storage pokemon and id rather not only train x amount of exp on it when i havent decided what i want to do, and sometimes people add onto training jobs, like they will get a second pokemon trained and when they get a training job they'll put that prize towards the other pokemon which then would mean re trading it and i think this would end up with more people quiting cause a pokemon only got 2 bil exp when they payed for an extra 3 bil afterwards and now can get it trained cause its level 15001

Not a Great Idea..
sometimes ppl want to extend after 15k+ so it will spoil their payment

No u are not understand it properly. If you require, then only you can use. Otherwise u can train as much as possible. If its required then u can use it. Thanx da man for replying it lol