Hello Bas, welcome to our forum family, and thank you for caring for the grave of one of our fallen.
As Marion has mentioned, it does seem confusing but i think we can clear the picture up a little from the info you have provided.
"in the report of burial stays that he was first mia on 21 dec 1944 found on 29 jan 1945 in schlausenbach germany"
Prior to the start of the Battle of the Bulge, The 106th Infantry relieved the 2nd Infantry Division on Dec 10/11 in positions covering the Shnee Eifel region near the Loshiem Gap.
On Dec 16, 1944, Schlausenbach was in the area of the 422nd Inf Regiment of the 106th Infantry Division. This map is from the book: A Time For Trumpets, by Charles McDonald shows the positions on the 106th.
exerpts from the After Action Report of HQ 106th Inf for Dec 1944
http://www.indianamilitary.org/106ID/Reports/106thAAR-12-1944/106thAAR-12-1944.htm
"At 170630A December, the enemy succeeded in penetrating the sector of the 423rd Infantry in the vicinity of BLEIALF. He pushed some forces north from BLEIALF while other enemy forces advances south from ANDLER, the two forces effecting a junction in the vicinity of SCHONBERG during the morning. This cut direct communication by road and wire between the units east of the BLEIALF – SCHONBERG ROAD and the remainder of the division. The units cut off were the 422nd Infantry, 423rd Infantry, 590 Field Artillery, part of the 589th Field Artillery, Co B 81st Engineer © Bn, Co B, 331st Medical Bn, Co C, 820th TD Bn and Btry D, 634th AAA (AW) Bn (M). Radio communication was maintained with these units until late 18 December.
It is presumed that the 422nd Infantry Regiment, 423rd Infantry Regiment, 589th FA Bn, 590th FA Bn and the 106th Reconnaissance Troop were eventually overpowered by the German forces east of ST VITH and the bulk of the personnel captured about 19 or 20 December. The strength of the German attack in the division sector and the forces available to the division at the time prevented their being relieved. Attempts to supply the units by air failed because of the weather, although, as learned later, two drops were made but not within their reach. It is known that they were still in the fight early 19 December. It is also known that prisoners were taken by the Germans. However, the final chapter in the defense of the SCHNEE EIFFEL penetration of the SEIGFRIED LINE held by these units is not now known."
Some individuals & small groups of men of these units avoided surrendering & tried to work their way thru german lines back to St Vith during the next few days, some made it, some didnt. According to most accounts there were 2 companies of the 81st CE with the forward units on the Shnee Eifel. Company A was attached to the 422nd Regiment during the time frame of Mr Timmers death. I think Co B was with the 423rd. Since all the regiment commanders & HQ staff of the 422nd & 423rd were captured & their records lost or destroyed, Division HQ staff would have had to do the missing in action & KIA reports several days or even weeks later.
"found on 29 jan 1945" "in the document ; restricted inventory of personal effects stays that he he was served [unit 8 inf] organisation 4 div] i dont know what this means"
Here, i`m guessing his body was recovered by the 8th Infantry Regiment of the 4th Infantry division but i havent found info yet placing the 4th ID in the area on Jan 29.
What an angel. Great sleuthing Sherlock!!! 
