A first installation occurs at the relevant 1st Pentecost festival date, a 2nd installation at the 2nd Pentecost festival date, a 3rd at the 3rd and so on

Under law if someone celebrated Nisan14 then then had to give their first fruits offering on 1NC first fruits. Then they should celebrate the 1NC Pentecost. But if they failed to do that they could celebrate instead the late 1NC Pentecost. Since some people must have done that, their actions establish a necessary prophetic fulfilment wherein an installation occurs at the late 1NC Pentecost. We can take this further - all the way - as follows...

The 1st group is appointed/installed to rule over the 1NCs at 1NC first fruits/the 1NC Pentecost
The 2nd group is appointed/installed to rule over the 1NCs at the 2nd occurrence of a 1NC first fruits/Pentecost which may be the 1NC first fruits/the late 1NC Pentecost or may be 2nd 1NC first fruits/the 2nd 1NC Pentecost
The 3rd group is appointed/installed to rule over the 1NCs at the 3rd occurrence of a 1NC first fruits/Pentecost which may be the 1NC first fruits/the late 1NC Pentecost or may be 2nd 1NC first fruits/the 2nd 1NC Pentecost
The 4th group is appointed/installed to rule over the 1NCs at 2nd 1NC first fruits/the late 2nd 1NC Pentecost

The 1st group is appointed/installed to rule over the 2NCs at 2NC first fruits/the 2NC Pentecost
The 2nd group is appointed/installed to rule over the 2NCs at late 2NC first fruits/the late 2NC Pentecost
The 3rd group is appointed/installed to rule over the 2NCs at late 2NC first fruits/the late late 2NC Pentecost

The 1st group is appointed/installed as priests over non adamics at Zoar first fruits/The Zoar Pentecost
The 2nd group is appointed/installed as priests over the non adamics at late Zoar first fruits/The late Zoar Pentecost.
The 3rd group is appointed/installed as priests over the non adamics at late Zoar first fruits/The late late Zoar Pentecost.

Generally: the first appointment over a particular group of people occurs at the first date for a festival, and the 2nd appointment over that group occurs at the 2nd possible date for said festival.

The 2nd presence wing of the 3rd Holy Spirit was married on 2015Ab21 (a 2nd marital appointment but delayed by three months due to the war of Revelation12 and Deuteronomy 24:5 - the Dragon's heavenly Passover was 2015Ab14 - see Revelation12 in U151) and so joins their installation as Aaron to the 1NC reserves subject to the Kingdom/Watchtower 1NC Alienation Times from 2008Tammuz9 (a 2nd appointment after the 2nd Holy Spirit) - 2015Tammuz9 and over the 2NCs but subject to the Kingdom/Watchtower 2NC Alienation Times from 2008Tebbeth21 (a 2nd appointment after the 2nd Holy Spirit, 2008Heshvan2 was not 2nd 2NC first fruits because 2008Heshvan was a Sabbath month) - 2015Tebbeth21. However the 3rd Holy Spirit must then be appointed as Aaron to Zoar at some point.
FDS4 was maledicted by the LW 1NC Alienation Times for 7 years to 2002Tammuz10 to 2009Tammuz10 (2nd 1NC Pentecost to 2nd 1NC Pentecost). The were appointed/installed to rule over the 1NCs on 2002Iyyar21/Tammuz10, 2nd after FDS3. 
FDS4 became operational in ruling over the 1NC reserves on 2009Tammuz10 and was reappointed/reinstalled as Abrahamic non adamics to rule as Levi over them on 2012Tammuz17/Elul6 (4th after FDS3, adamic FDS4 and adamic Laodicea). 
FDS4 was again appointed/installed to rule over the 1NCs on 2013Elul22/Heshvan11 (5th after FDS3, adamic FDS4, Laodicea, non adamic Abrahamic FDS4 - 2013Ab was a Sabbath month)

Elijah4 was appointed/installed to feed the 1NCs on 1998Heshvan2/Chislev21 (2nd after FDS3) after their 3 accountable Passover denials on 1996Nisan14/1997Nisan14/1998Nisan14 and after FDS3 fell over the saints on 1998Tishri27
3 years of the fundamental pattern of U42 later, Elijah4 was appointed/installed to rule as sacred king over the 1NCs on 2002Iyyar21/Tammuz10 (2nd after FDS3) and immediately maledicted by the LW 1NC Alienation Times until 2009Tammuz10.

Elijah4 was appointed/installed to feed the 2NCs on 1996Nisan18/Sivan7 (1st) after being thrown out of the Watchtower on 1995Adar11.
3 years of the fundamental pattern of U42 later, Elijah4 was appointed/installed to rule as sacred king over the 2NCs on 1999Tishri2/Chislev21 (1999Heshvan was a Sabbath month).

Laodicea were appointed/installed to feed as priests the 1NCs on 2003Chislev2/Shebat21, 3rd 2NC first fruits/the 3rd 2NC Pentecost (3rd after FDS3 and FDS4 - delayed from 2003Tebbeth21 by the Sabbath month). 
3 years of the fundamental pattern of U42 later, the Laodiceans were appointed/installed to rule over the 1NC reserves on 2007Sivan22/Elul11 (3rd 1NC first fruits/the late 3rd 1NC Pentecost - 3rd after FDS3 and FDS4 - 2007Ab being the Sabbath month). So Elijah4's instruction to celebrate the late Passover on 2006Iyyar14 was valid - since neither FDS4 nor Laodicea had rulership. But Laodicea did have an installation to feed the 1NC reserves.  
Laodicea fell over the 1NC reserves on 2012Sivan14, when they died to Adam. 

At last we fully understand what a Pentecost is. God is plainly Swiss-German!