An important point I think is that while the experiences of others are often helpful, it seems to me that this is a very individual experience and the best way to progress can be different for each person. On the other hand, M0WAS and I do seem to be having somewhat similar experiences.
This is all correct - no one knows anything about you - so how can anyone advise you what you should be doing.
Also the main factor in learning morse is APTITUDE, which comes from a mix of the full range of the different factors involved eg.
motivation ( are you in two minds now after all this time exercising )
correct level of concentration ( do you sit down to lcwo and start dreaming or thinking about work tomorrow ?)
relaxing and letting you brain do the work ( without letting your imagination drift)
hearing ( can't hear it - can't learn it - do your ears distort sudden noises like bips or do you need to choose a better audio frequency ? )
headphones ( comfortable ? / distorted sound ? too loud/soft ? )
background noise ( are you listening for what the kids/dog are doing )
disturbances ( are the kids or dog actually doing something ? )
are letters / spelling your thing anyway ?
We can however point out a few traps - like :-
getting keyboard bound
wizzing ahead as far as exercise 10, then finding it didn't sink in properly and that now you need to re-do it all
not making progress and giving up due to boredom
The drop out rate seems to be rather high - maybe 90% of starters think it's easy to learn morse, and get disillusioned.
Generally we advise getting through the exercises well before you get fed up ( if not ASAP ) - and then worrying about speed.
i.e. not doing a exercise at 25/12 than 25/ 13/14/15 etc
So you don't have to exercise at 20 or 25 wpm. 10/2 will do if it gets you through . . .
If it's quicker to get through the exercises, you may be better at 18/15 ( try 17/17 ) than 25/12.
Then think about speeding up - when you can decode whole passages of text for practice.
Don't worry too much about "i s h 5" issues either at this stage.
As you become proficient and your hearing gets attuned, morse will seem to get slower somehow allowing you to speed up . . .
Note:- YMMV - we don't know anything about you ( did I mention that ? )
If you are one for tricks-of-the-trade, then try a faster rate then you can handle for a couple of mins
- then drop back to your normal rate for the lesson session.
Seems to help some people.
In the end though its - repeat, repeat, repeat, until it becomes second-nature and you can decode without really having to think about it.
It's worth it in the end.
Good luck - enjoy.
Let us know how you are getting on . . .