Progressions don't work the same way as Solar Arcs. I would add that I'm not an authority on Progressions, but basically, using the ephemeris, you count the days from your date of birth, to your current age. eg. if you were born say on 20th Sept. 1980, you would be 28 now, so in the ephemeris, you would count forward 28 days, and would arrive at the planetary placements on the 18th October of 1980.
For the House Cusps, you add your age to the MC,(count forward at 1 deg. per year...eg. if you had say, 9 degs of Gemini on the MC, then in a Table of Houses - you would count forward 28 deg. which would give you 7 degs. of Cancer on the MC, and then you would look at the latitude of your birth in that Table of Houses - according to whichever House system you use - to see where the house cusps are. (You probably know this already, but am mentioning it as you said that
In the beginning though I thought it was odd that you would progress the outer planets by the same amount as the Sun.
and I may have misunderstood about your knowledge of Progressions.)
This is a very simplistic description. (Hopefully our Progressions expert, janedeflorez, will be back soon and explain it more ).
Solar arcs are counting the years between the individual planets, and between planets to Asc/Desc/MC/IC. If for eg. you have say, 28 degrees between Sun and Uranus, then, around the age of 28 you would (theoretically) experience a strong need for independence, and a breaking away from what has become 'static' or from ways that no longer work for you. If the Sun is 28 degrees from the MC, then at age 28, there may be a period where you become recognised in your profession, and/or have confidence to move ahead in your vocation. It could also mean recognition by a parent. It all depends on the 'state' of the planet at birth.
For eg, and going back to Hitler's chart,
During the final days of the war in 1945, as Berlin was being invaded by the Red Army, Hitler married Eva Braun.[3] Less than 24 hours later, the two committed suicide in the Führerbunker.
(Wikipedia). His Mercury at 25 Aries, was
55 degs. (Years) from his 'Black Moon' in the 20th deg. of Gemini in the 8th House. Mercury rules his 9th and 11th and is the dispositor of his 'Black Moon' in Gemini. Hmmm. Will have to ponder on that.