OK so, I did the math and it didn't work out as I expected it to.
Media Create Sales:
Week 04, 2018 (Jan 22 - Jan 28) 01./00.
[PS4] Monster Hunter: World # <ACT> (Capcom) {2018.01.26} (¥8.980) - 1.245.169 / NEW <92,07%>
Week 05, 2018 (Jan 29 - Feb 04) 01./01. [PS4] Monster Hunter: World # <ACT> (Capcom) {2018.01.26} (¥8.980) - 346.187 / 1.591.356
(-72%)
Week 06, 2018 (Feb 05 - Feb 11) 01./01. [PS4] Monster Hunter: World # <ACT> (Capcom) {2018.01.26} (¥8.980) - 159.613 / 1.750.969
(-54%)
Week 07, 2018 (Feb 12 - Feb 18) 01./01. [PS4] Monster Hunter: World # <ACT> (Capcom) {2018.01.26} (¥8.980) - 85.322 / 1.836.291
(-47%)
Week 08, 2018 (Feb 19 - Feb 25) 01./01. [PS4] Monster Hunter: World # <ACT> (Capcom) {2018.01.26} (¥8.980) - 53.982 / 1.890.273
(-37%)
Week 09, 2018 (Feb 26 - Mar 04) 01./01. [PS4] Monster Hunter: World # <ACT> (Capcom) {2018.01.26} (¥8.980) - 38.617 / 1.928.890
(-28%)
Week 10, 2018 (Mar 05 - Mar 11) 02./01. [PS4] Monster Hunter: World # <ACT> (Capcom) {2018.01.26} (¥8.980) - 25.382 / 1.954.272
(-34%)
Week 11, 2018 (Mar 12 - Mar 18) 06./02. [PS4] Monster Hunter: World # <ACT> (Capcom) {2018.01.26} (¥8.980) - 16.614 / 1.970.886
(-35%)
Week 12, 2018 (Mar 19 - Mar 25) 08./06. [PS4] Monster Hunter: World # <ACT> (Capcom) {2018.01.26} (¥8.980) - 13.329 / 1.984.215
(-20%)
Week 13, 2018 (Mar 26 - Apr 01) 10./08. [PS4] Monster Hunter: World # <ACT> (Capcom) {2018.01.26} (¥8.980) - 10.011 / 1.994.226
(-25%)
Week 14, 2018 (Apr 02 - Apr 08) 11./10. [PS4] Monster Hunter: World # <ACT> (Capcom) {2018.01.26} (¥8.980) - 5.189 / 1.999.415
(-48%)
Week 15, 2018 (Apr 09 - Apr 15) 16./11. [PS4] Monster Hunter: World # <ACT> (Capcom) {2018.01.26} (¥8.980) - 3.640 / 2.003.054
(-30%)
Week 16, 2018 (Apr 16 - Apr 22) 18./16. [PS4] Monster Hunter: World # <ACT> (Capcom) {2018.01.26} (¥8.980) - 3.103 / 2.006.158
(-15%)
Week 31, 2018 (Jul 30 - Aug 05) 19./00.
[PS4] Monster Hunter: World [1][Best Price] # <ACT> (Capcom) {2018.08.02} (¥4.990) - 4.889 / NEW <15,70%>
Week 29, 2019 (Jul 15 - Jul 21) 00./00.
[PS4] Monster Hunter: World [2][Best Price] <ACT> (Capcom) {2019.07.18} (¥2.990) - 3.378 / NEW <30,20%>
Week 36, 2019 (Sep 02 - Sep 08) 01./00.
[PS4] Monster Hunter: World - Iceborne Master Edition <Monster Hunter: World \ Monster Hunter: World - Iceborne> # <ACT> (Capcom) {2019.09.06} (¥6.990) - 171.129 / NEW <54,26%>
Media Create Sales: CY 2019 (2018 Dec 31 - 2019 Dec 29)
014./000.
[PS4] Monster Hunter: World - Iceborne Master Edition <Monster Hunter: World \ Monster Hunter: World - Iceborne> # <ACT> (Capcom) {2019.09.06} (¥6.990) - 443.388 / NEW
100./170. [PS4] Monster Hunter: World [1][Best Price] # <ACT> (Capcom) {2018.08.02} (¥4.990) - 45.537 / 69.635
(+89%)
104./000.
[PS4] Monster Hunter: World [2][Best Price] <ACT> (Capcom) {2019.07.18} (¥2.990) - 42.362 / NEW
870./002. [PS4] Monster Hunter: World # <ACT> (Capcom) {2018.01.26} (¥8.980) - 1.189 / 2.031.129
(-100%)
Shipments:
As of January 28, 2018:
around 2 million units on PS4 (5 million units worldwide, 60% of that outside Japan, source: Capcom, via
Mochizuki)
As of August 20, 2018:
around 2.9 million units on PS4 and PC, including Best Price SKU (over 10 million units worldwide, 29% of that in Japan, source:
Capcom, via
Famitsu)
As of early October 2020:
3.184.000 on PS4 + 236.000 on PC, total 3.420.000 (source: Capcom data leaks)
Let's take "around 2 million units" as 2.000.000 and "around 2.9 million units" as 2.900.000 and see what happens.
First week physical shipments for World are estimated to be 1.245.169 / 0,9207 = 1.352.416 units.
If World shipped 2.000.000 units in 3 days, then digital sales were 2.000.000 - 1.352.416 = 647.584 units, a 34% digital share for sell-through.
Initial shipments for the first Best Price SKU are estimated to be 4.889 / 0,157 = 31.140 units.
Since Capcom launched this SKU, it's safe to assume that they didn't ship any additional copies of the base SKU afterwards, which means that its LTD physical sell-through as of December 29, 2019 was already shipped by August 20, 2018.
Thus total physical shipments as of August 20, 2018 are estimated to be 31.140 + 2.031.129 = 2.062.269 units.
If World shipped 2.900.000 units by that point, then digital sales on PS4 and PC were 2.900.000 - 2.062.269 = 837.731 units.
In this scenario, from January 28 to August 20, physical sales for World increased ~815k while digital increased ~190k, including the PC launch.
Seems possible so far. But here comes the problem: afterwards and as of December 2019, Capcom shipped at least 443.388 + (69.635 - 31.140) + 42.362 = 524.245 physical copies to retailers. Iceborne Master Edition continued selling in 2020 (74k according to Famitsu), so you would expect total shipments as of early October 2020 to be a decent amount over 2.900.000 + 524.245 = 3.424.245 units, but they're actually reported lower at 3.420.000 units. Does this confirm that Capcom does not include the Master Edition sales into World figures? If so, then World actually sold a lot on the PSN when its price dropped and its total including the Master Edition and PC version would be around 3,9 million units. Or maybe the leaks are incorrect, or I might have made a mistake while writing this, if so then please feel free to correct me lol.